First, watch this:
So here's my bone to pick, and I've been seeing a lot of this lately: Paintball and airsoft M203 grenades pack a serious punch. Would you stare down the barrel of a loaded, charged and cocked paintball gun at point blank range? Well then why is everyone staring down their M203 grenades? There are no built in safety mechanisms in them, and if an o-ring fails his grenade could discharge spontaneously.
In the individual case looked at here, it is revealed that the grenades were charged prior to loading, so at the beginning of the video the guy loading the shell is risking his vision or worse. So while I'm kind of picking him out amongst the crowd, he acts as a good poster boy for failing to use your common sense when dealing with dangerous paintball equipment.
We all make mistakes, and I'm not outright calling this fellow an idiot, but this is certainly a boneheaded move.
