A lot of places use aerial photography to make these kinds of checks, though some of the items seem small enough to have been inspected by someone who on the ground. I've heard of people being busted by the county for building decks without permits.

Anyway, it's surprising. I'll have to re-examine my policy to see if it creates an easement for them to stop by or if they would be trespassing.

RE: Be careful if you get the 'drive by' check letter from State Farm