Front plates have not existed in Pa. in my lifetime. Perhaps they did, say prior to WW II? About 5 or 6 years ago, our DOT abandoned the yearly renewal stickers that you placed on the rear plate. At the time they did that, they used every available media source to proclaim that every police patrol car in the US had a plate reader onboard. That turned out to be wildly incorrect at the time. Anecdotally, most of the trouble stories seemed to come from Pa. drivers in Md. I have 4 plated vehicles and I have no idea when the registration on any of them expires. Unless I dig out the registration card. Prior to that change, the due date for your yearly safety inspection was typically the same month that your registration expired. No longer.
We are still one of about 7 states that has a yearly vehicle safety inspection. Up until the mid 80's, it was every 6 months. Someone mentioned the prevalence of illegal level dark window tint forward of the B pillars. I see it all day every day. There is evidently zero chance of being cited for it or an expired anything by local law enforcement.