What did you expect?

On my way home from work last night I stopped at a gas station to pick up a snack.  As I was getting out of my car I noticed a guy filling his tank while smoking a cigarette.  Not only did I think about how stupid that was, but there was a cop parked right there (looked like he was filling out a report).
 
Well, as I was paying for my food, I hear this blood-curdling scream and, guessing what had happened, turned around to see this guy with his arm in flames waving it around like a complete idiot!  The cop jumped out of his car and knocked the guy to the ground putting out the flames.
 
As I was walking back outside the cop was cuffing him and putting him into the squad car.  I realize the guy had been stupid, but I asked the officer why he was arresting him...
 
"I caught him waving a fire arm" was the reply.

I can't believe I was fooled by this old chestnut. The worst of it is, as soon as you mentioned his arm on fire, I thought "oh I'll make that crack out him being arrested for being in possession of a firearm." Lo and behold, you were setting up the same joke. I must be getting slow....