Well, you need to define better what is your operational objective: Do you NEED to prevent "infugees"? Or just to keep a copy of any ego that tries to escape? Or are you trying to get a certain ego you are unable to identify without some VR interrogation/ego ID? If the latter, having a look at Nine Lives, the ID Crew and other egonapping rings described in the setting. For a military op, it would be easier to set up "man in the middle" or Sniffing attacks that capture whole egos if enough time is provided to the infiltrators. If you need to avoid anyone to leave, even at the "risk" of definitive death to that ego, or even wanting to, then as mentioned you can neutralize transmission systems (cutting the cabling in the exterior of the hab would work better than blowing stuff... a series of failures over a few weeks on several farcasting facilities would serve to locate "underground" ones)... that won't block Farcasters, who are a very expensive "last ditch escape" system, however, so we need to be imaginative here. My suggestion is to generate a disrupting pulse to scramble the output signal, but that will "kill" or degrade the scaping ego, there is no way to capture and decode an ego using a Neutrino Farcaster per the rules.