Oh yes, the agent entered my house. He called from the street first to let me know he had measured my signal and it was over the Part 15 limit. He showed me his credentials at the door and again asked for permission to enter the house. He was very friendly once he discovered that I was going to be cooperative and wasn't hurling epithets. He even complimented the sound and said he loved the tunes and the old jingles. He was near my age (49+).
The agent asked me if I would voluntarily forfeit the FM100B which I did (goodbye $400). Naturally I asked who turned me in and why and he (naturally) would not say. But he did confirm that in no way did my signal interfere with any licensed stations, just that the strength was too high and that the person who complained reported hearing my station 10 miles away. Ten miles on a quarter watt?? I laughed and said, what did they use, antennas from the old Viking Mars mission? Nope, plain old car radio. I figured that had to be a spoof, something outrageous to make the complaint seem serious enough for a field visit. Either that or the skip was working great one day.
When I was living near Raleigh NC I once caught the old Magic 102.9 from Dallas. It was so clear I would have sworn it was a local station until I heard the calls. I should have filed a complain about excessive RF. ;D