The only thing that I have found that vaguely addressed that is the 'interference with visibility of license plate'.
Course that was when I lived in So. Cal. and CHP's used as an excuse to pull over vehicles......license plate frames was another one.
I hate them sticking out on my truck or anyone else....shin knockers.
Don't like the locking pins either......always a pain to get them unlocked. Dirt, mud, grime in key way...rust etc.
So I always use a standard pin and just remove when not needed......get stolen otherwise.
