Loki may be able to learn more about what's ICly known by other Voidtreckers, but there is apparently - by how Loki was caught and set up - a way that the whoever is behind this can tell what's being done, to some degree.

Doing minor dispelling may not attract attention, but anything larger will lead to more consequence (as suggested before, when I believed he was attacking multiple buildings on a larger scale). It will become far more difficult for him to move around, depending on how far he takes it.

Those he has been in contact with will also be targeted the more he tries. And it's possible that not just the D-Force/people in the city will be sent after him.