I will assume that wormholes behave different under different conditions and that the player characters may choose under those conditions as they see fit.
If a wormhole mouth is accelerated, a time machine has been created. The relativistic shift between the two mouths of a wormhole is the time span one could travel into the past. Lets now say that the wormhole mouths are closer to each other than the distance which is equal to the speed of light multiplied with the time span of the relativistic shift. If one travels from mouth A to mouth B into the past and sends a radio signal back to point A, this signal will arrive at point A at a time before the traveler has entered the wormhole. He must have received this signal in the past, otherwise causality would be violated.
This should be the normal behavior of wormholes, because the past cannot be changed. Let’s now assume one could configure wormholes in such a way that a violation of causality would in theory be possible. In this case, in order to prevent the possibility of violation of causality, let’s say that the so-called Visser Effect will occur: If the two mouths of a wormhole belonging to a time machine came closer to each other than the above specified distance, the wormhole will be neutralized.
Clearly, even if the two wormhole mouths are not close enough for the Visser effect, one could violate causality by traveling back to mouth A by use of a second wormhole. Therefore, the Visser effect has to neutralize “all” wormholes (like a Wormhole Interdiction Field) and all other means of FTL communication in order to prevent the possibility of violation of causality. This includes the Alcubierre drive as well as the FTL Communicator which is based on Chronotech (see there). In fact, all Chronotech within a radius which is equal to the relativistic wormhole mouth time shift multiplied with the speed of light would therefore be neutralized: The Chronotech Interdiction Field
