> So many cars in my apartment complex have MD plates

If they're students going to school here, their license & registration can still be under their "official" residence at (usually their parents') out of state address.

I moved to PA while a college student, had a non PA car & DL for years. Was perfectly fine.

Officially living in PA was a bit tricky because 1- I was poor and had an older vehicle, 2- I came from a state where older vehicles are not issued titles when purchased used, 3- PA requires all registered cars no matter how old to have titles, so 4- I had to scrap my fucking car for $80 in cash because no one would buy it, it couldn't be registered, and my landlord & the township was about to impound it as derelict :(