Officer, I was wearing my seat belt!

Everybody knows that law enforcement hears the "Officer, I was wearing my seat belt" excuse all the time, right? Apparently not.

I recently got a ticket for not wearing my seat belt. I did take it off momentarily to reach to the floor at a red light for my sunglasses, which had fallen from the visor. When I explained this, the officer's eyes gave me that "Sure, buddy" look. Why would he not believe me?

If this guy was a teacher, would he believe a student who said "The dog ate my homework"?