It seems there are more and more violent incidences happening in the sport. I only got out to about five events this past year here in Edmonton, and witnessed two myself.
Both cases involved an argument over if one player was "dead" (the classic "you! you are dead! I SHOT YOU YOU ARE DEAD!!!!" issue). The first involved a player becoming hysterical and emptying a magazine into the object of their rage at arms length. The second was simply a case of a player again, demanding a player remove themselves from play and insisting they had been hit by fire, then (i watched this happen) making a very calculated, purposeful decision to as the last case, empty an entire magazine into their foil as "retribution" of a sort.
In both cases, the players were not expelled from the game nor disciplined in any way. I think it's up to game hosts/field owners at this point to start cracking down on this bs and adopt a no tolerance policy for this kind of stuff.