This is the strangest reason I've ever been stopped for.
I was traveling on our interstate and needed to get over in one of those extended onramp lanes. But the traffic was stopped on the adjacent lane that exited also. So I stopped (from 5 mph) and turned on my right turn signal to get over.
A state patrolman pulled me over and when he got to my window he asked me "DID YOU JUST STOP BEFORE TURNING ON YOUR SIGNAL?!". Well yea, but about 1/4 second after I stopped.
He informed me "that's how people get rear-ended! Even though it wouldn't be my fault." What a cheese ball.
I think he realized how stupid he was being because after he said this he quickly returned my license and went back to his car. Didn't run my license or plates or any of the usual stuff they do around here.