... when you see an idle player (standing still, "not playing", maybe typing)?
I shoot him in the leg to see if he'll move, to finish him off. If he's still not moving, I move along... Don't want to bulid my K/D on some poor guy being idle.

Maybe if there is more of stupid players like me, someone could "play dead" like in UT3 xD I could be killed if I turn my back. xD

So what you do when you see an idle player?
Do you have any interesting videos? (maybe this becomes nasty)