Not really...As in, it's technically illegal in some states, but sometimes tag bureaus are really stupid. There was
an actress years ago that was stalked, the stalker went to the driver's license bureau and received a copy of another's registration for a few bucks, and that's all that psycho needed.
I say stupid because I lost my registration back in 1999; couldn't find it anywhere, so I headed over to the driver's license bureau with my wife. They asked "what's the tag number". I told them the tag, and three dollars and zero identification required, there's my registration slip with license plate, make, model, VIN, name, and address. I told them..."you know, I could have been anyone asking for that information", and showed them my ID as a form of goodwill. So it's a bit of a sore spot to me, which has likely changed in this day and age.
Most cops aren't stupid; many of them read car magazines. They know when something looks a little out of place (never saw one of these before?) The question is, do they really want to waste time for an impound vehicle, knowing that the said offender is likely to draw revenue-seeking attention once again? Might as well catch, (ticket,) and release. I suppose there's always one or two that think they're doing something heroic/covering their blue-clad behinds/by the book.