PBFOT is a little trickier. Let me see if I can help you out. Pb is the 82nd element, lead. FOT, I assume, is supposed to mean foot. Put it together and you have Lead Foot. And I'm pretty sure most of the cops pulling you over will not think this is funny. (Photo snapped by Bonnie Z.)
And finally, another user-submitted photo from Dawn:
I can’t believe that you don’t have one TN tag in your collection. . . So I am sending you one – mine. And, yes, I pick one up.
Aaaaand Tennessee enters the game with a perfect addition to the vanity plate Hall-of-Shame. Congrats.