So, for example, NY requires yearly safety inspections and you'll get a ticket if your inspection lapsed. But you don't have to get a safety inspection to drive in NY if your car is registered in a state that doesn't require safety inspections.
I could be mostly off base on this one.
Though some laws are so local sometimes it's impossible for an out of towner to know the local laws like going right on red is, as far as I know, illegal in NYC but legal... Everywhere else? How does someone from Texas supposed to know that?