Got pulled over with my full-sized plate right before the Keystone Ferry (a permanent cop trap). Cop said he couldn't see my trailer licence and that is why he pulled me over but said that once i pulled over, he could see it. Um...? Still bothered checking my ID, registration, etc. No issues but still thought it was BS.

Seems like the small ones (I have one of those on another trailer) are so small that that you'd practically have to be stopped for them to truly ID it.

Unfortunately, when you are towing a trailer, you are a lot more likely to pulled over. If it isn't the licence plate, it is the constant trailer-light battle. If not that, they can now pull you over for having ANY vegetation on your trailer or boat.