This is a disturbing trend in human evolution. Why when how did we get to the place that people feel it is okay to enter the locker room uninvited - much less attack anyone???
So what can be done from the referees to de-escalate these "events"?
When calling fouls or ejections - take the emotions out of the call. This is tough because everyone gets wrapped up in the flow of the game. Often these events take place because both sides are emotionally charged. If one is non-emotional, it usually leaves the other side an avenue for release. The only exception is for the plate umpire in baseball - normally people enjoy seeing the animated calls.
I also feel that the allowance of letting people fudge on the rules has contributed to these events because no two corner-cutting are the same. For instance, look at dribbling in basketball; we have allowed the underhand carry so much that I know longer know when it is a carry or dribble. Same with traveling. Last night I watched Duke win on the last shot after the player took 4 steps - jeez Maloney. We will allow four steps but god forbid a player lets his sneaker squeak 1 inch and that is traveling.
How about football with all the talk of concussions these days? We allow spearing and practically NEVER call it. In fact, players are taught to put there head on the ball to dislodge it - but we NEVER call it. How about the practice of slapping at the ball to knock it loose? That has turned into punching and if you don't hit the ball, be sure to hit something (i.e. Ribs, kidneys, gut) - but it is never called! We have allowed aggression to be allowed into these games - and that aggression flows into the stands.
As far as hockey goes, I went to one game many years ago - all it was was a brawl on ice. I have never watched again. People go to watch the fights, not the game. Just like Nascar, people go to watch the wrecks, not the race.