The FCC only needs a mailing address and they can come inspect your station any time they feel like and don't need a search warrant
Funky...I know that's what the study book says but that's not entirely true. FCC field agents need probable cause and evidence such as recordings or EFI documentation to enter your home to inspect your station, including a court order.
I've worked with field agents several times RDF'ing suspected broadcast violators. Even though we listened over the fence to the broadcast being re-transmitted, they could do no more than knock on the door and ask questions. If turned away they have nothing, because the suspects would just cease and desist and move the radio gear. It's a cat and mouse game with these types and they know it.
The FCC is very lenient in their licensing procedure. If you retire and sell your home, purchase a motor home and tour the country, then where is the station? People do this, establish a P.O. box, pick up the mail when ever, and it's recognized. I hold two other licenses, one is a City club license and the other a Govt. club license, and all that's required is a P.O. Box. Over the years as a VE and a VEC, I have processed maybe thousands of licenses and never has one been rejected because of a P.O. box as an address.