Last summer I was coming home from a 7 day old car tour. Along the way my brake lights stopped working. I made it to within 2 miles of my house when a sheriff's car pulled me over. I figured he noticed the brake lights. Nope, he wanted to know about my YOM plate.
These plates are legal in Vermont and easy to get. The cop had never heard of it before. I had the current plate and registration in the car as required. I also had a printout of the Vermont statute on YOM plates -- a nice and helpful (yes, nice and helpful) guy at the DMV advised me to carry it as "someday you'll run across a cop who doesn't know the law."
So I showed all that to the cop and he let me go and thanked me saying, "You saved me a lot of time. I would have had to look through a book 3 or 4 inches thick trying to find that." He never mentioned the brake lights.
Pete