A guy built my FM transmitter then he saw the RF cops driving down his street the next day after he tested it. Their van moved slowly and had a rotating yagi antenna on top.
When I was a teenager I made a fan with a badly sparking motor. The RF cops found me and we had a nice chat about electronics, and that my fan was interfering with many TVs. They didn't shoot me and they didn't chop off my head.
The people who complained about my interference bought me a new fan.