Feel free to ask questions and I'll see what I can do.
On Cities and Ambient Mana Usage Norms:
In a typical area there's a large amount of mana available to everyone, and it replenishes very
quickly – even if someone constantly uses moderate amounts there's enough to go around. Generally speaking, this subject is only grounds for concern in the most population dense cities, however even less populated cities may need to take the principles here into account to avoid a tragedy of the commons scenario if they possess a region with exceptionally valuable mana. Failure to account for ambient mana conservation risks turning the city into a null zone, and in the worst case scenario, may provoke a war with rimward neighbors.
A cities ambient mana and leylines are what in the works of Elinor Ostrom is referred to as a common pool resource, with traits of a fugitive resource given the tendency of mana to flow. Three approaches to averting tragedies of the commons exist, the first is to put the Common Pool Resource under state control, the second is to privatize it, and the third solution involves sufficient community organization to ensure people do not engage in wanton use of ambient mana.
Summary:
No player character can expect to do anything with a large or tremendous mana draw in a sufficiently population dense city without attracting hostile attention from community mana monitors, irritated passersby, or more formalized law enforcement bodies if they have not sought permission from the local government, mana management corporation, or community mana association. Filling a large number of moderate sized mana jars in succession is likely to get hostile looks too. If a player character is not a citizen of the city they are drawing excessive amounts of mana from, they will find themselves outlawed at best or provoking a political incident in the worst case scenario.
Cities typically have designated ritual sites for the use of their citizens to perform large scale magical workings and fill mana containers larger than moderate size. What it might take to get time in a ritual site varies by civilization and the needs of the plot. For example, ritual site time may be tradable as a form of currency if the trading parties get it on record with the government or community mana association. Ritual site usage reports may be filed with the government for taxation purposes(Taxes are typically paid in various aspects of mana where applicable, though taxation in kind is also possible).
Detailed explanation/Community Mana Organization 101:
The bolded things are phrasings of the principles recognized as common to successful attempts at common pool resource management by communities. There's another formulation in Ostrom's wikipedia article. https://en.wikipedia.org/wiki/Elinor_Ostrom#Design_principles_for_Common_Pool_Resource_(CPR)_institution
Clearly Defined Boundaries
A city with regions of mana with a highly desired aspect within its boundaries can expect people seeking the mana to come from other cities, possibly to steal it, and citizens engaging in excessive consumption of mana for market purposes or whatever projects they may be pursuing. To stop this, particularly population dense cities lock down their travel grids in the style of the Geometers, and have designated ritual sites with regulated access for large scale magical workings, which may provide ley line access.
Appropriation Rules tailored to local conditions
Generally speaking, central regulators are unlikely to be able to know things like the details of a cities mana and aspect flow with extremely precise detail. The time necessary to greenlight null zone protocols if a city loses hubward mana flow is faster if handled by a community mana association.
The Affected individuals have a say in the rules
Compliance with mana conservation rules generally improves when people believe the rules are within their ability to influence, which is why community associations are frequently organized along democratic lines.
Accountable monitoring services exist, people are able to watch each other
The ubiquitous presence of the Sixth Sense makes some level of monitoring ambient mana consumption practical for all members of the community. Small scale drawings on ambient mana are generally unnoticed and written off as a necessary part of civilization, but any mana draw above Moderate is extremely blatant to anybody in the area with a mystery rating of at least 2, and they are all taught to chew out, attack, file a lawsuit against, or report individuals engaging in reckless mana consumption to the proper authorities depending on their civilization/governmental structure.
Anyone with a mystery rating over 4 and proper tools can immediately spot the responsible party or parties for large mana draws even in a crowd.
Community monitors for ritual sites or reckless mana consumption in general, in addition to the possibility of being paid more conventional forms of payment such as salaries from their local mana association, may receive payment in the form of preferential or generous drawing privileges at a ritual site, and gain the informal benefit of being able to see for themselves how much people actually abide by mana conservation rules. Monitors may be elected, chosen by lottery, or by any number of other mechanisms.
Graduated Sanctions for Rule Violation(Context Matters)
Community Mana monitors generally have the authority to levy fines and/or file lawsuits depending on their particular civilization's legal structure. Penalties typically start lenient to account for city residents who may be in desperate circumstances but are entirely capable of escalating to outlawry for repeated offenders. Such mercy is not extended to noncitizens, who immediately find themselves outlawed.
Venues exist for easy conflict resolution
Communities frequently have specialized courts or forums for resolution of disputes over aspect flow and issues relating to ambient mana conservation. These forums may or may not have the backing of their city or central government, though their effectiveness noticably improves if they do. Complaints against mana monitors can also be levied in these courts.
Government isn't interfering
A corrupt or well meaning but ignorant government can easily run roughshod over a community's attempts to solve mana conservation problems.
Large CPR's may need to resort to nested enterprises
For a community to attempt to solve problems by forming a single mana association for a large population dense city, as opposed to division into regional mana associations that act as components for the larger association, heightens the risk of failure.
If several cities from the same civilization are fortunate enough to share a contiguous region, they may form an even larger mana association to handle regional scope issues.
Mana approach by Civilization:
Cult of the Empty Grave: Common Pool resources like ambient mana are regulated by the government
Diadem: Ritual sites are heavily privatized. Capitalism is alive and well here. Mana conservation norms have become a tool to widen the gap between the upper and the lower class.
Geometer's Guild: Common Pool resources like ambient mana are regulated by the environmental division of the Procurement branch of Geometer government.
Glimmermere: Glimmermere deal with the subject of ambient mana conservation via community organizing depending on the needs of the situation with sporadic levels of effectiveness
Golden Aegis: The Golden Aegis's overmind makes them particularly effective at dealing with ambient mana conservation via community organizing, with priority for ritual sites typically being bestowed on the basis of honor.
Hearth-Kin: Hearth-Kin deal with the subject of ambient mana conservation via community organizing depending on the needs of the situation, and are relatively effective at doing so.
Nova Commonwealth: Nova sects either use mana associations as the Worldbuilders do or let residents draw on mana as needed in a mix of intuition meets popularity contest. Inter-sect mana disputes are resolved by the Nova Commonwealth legal system.
Sovereigns of Hell: The ability of the Sovereigns to address common pool resource problems is essentially nonexistent. Given their cultural outlook, it would take a miracle for a Sovereign enclave to reach sufficient population density to need to worry about ambient mana conservation.
Those Above the Sky: As anarchocapitalists, mana drawing privileges are typically acquired by payment to the mana managment corporation(that in turn acquired recognition from the village castle/security company) responsible for an area in proportion to the desired consumption, while private homes have sacrosanct right to the mana within their sphere of influence barring economic transactions that may alter matters. Given the amount of mana attic lines provide, this is a relatively viable approach.
Unroyal: Unroyal typically deal with ambient mana management via mana associations/community organizing. They are better at it than the Glimmermere but their cultural outlook prevents them from reaching the levels of effectiveness the Hearth-Kin/Golden Aegis/Worldbuilders have attained.
Worldbuilders: Worldbuilders generally speaking, deal with issues relating to conservation of ambient mana via local district mana associations nested within mana associations for the entire city in elaborate public-private partnerships. Given their interest in planning for the future, community focused outlook, and the broad discretion granted to individual city states, they have become quite skilled at handling issues of ambient mana conservation.
