I've heard unconfirmed reports, I've never heard of a confirmed report of someone from the FAA showing up and checking registrations, they have better things to do for one and the FAA is largely educational over enforcement, even IF they bothered it would be to inform folks of the rules and maybe come back later and check on it.
Not saying it hasn't happened, it's possible, but it hasn't happened and been reported to us that I know of in any manner I would call confirmed and not second hand drivel