Well, I am again going to recount the story of when the pikeys decided to pitch up in the car park at work years ago.
MD was bricking it because they had to wait 14 days to evict them. We had customer seminars booked and all sorts. Meanwhile they were openly using the car park as a toilet and so on.
Anyway, first thing they did was set up the satellite TV, of course. Could see them through the window of the caravan havign a cuppa in front of the TV.
So, into stores and out with a 10GHz sweep generator and an EMC test antenna pointed in their general direction.
Switch it on. picture gone. Out he comes to adjust the dish <click> picture back. Wait until he picks up his tea <click> .. and back out to the dish <click> repeat until they get bored and clear off. Got rid of them in 2 days. 12 days faster than going through the official channels.

Kevin