Most of the FCC accusations are complaint-driven. I'd agree that for those who run illegal power, keeping a clean signal and avoiding transmitting when programs like sports or prime time TV/radio are on the air are the best ways to avoid trouble. The FCC now uses triangulation from automated computerized listening stations to locate the offending antenna to an address. They will send a vehicle around to precisely locate the signal.
FCC only cares if you screw with public services, and are handled by the local authorities. I live in a city and run maybe 3.2kw, but on the vertical side I have 2% loss and on the flat I have .126% loss. Vertical has a slightly higher match which will be dealt with, but doesn't screw anything up around me.
High Frequency Direction Finding Center Pirate Radio Monitoring mostly VHF and up is done from some regional offices but its nothing like the scale of the old full spectrum monitoring stations that were closed in the 1990s.
