[Pat Arnold]

Fan etiquette affects all spectator events (& I doubt we'll resolve it here):

From a Hockey site:

Etiquette has become a 'bigger' problem it seems in our non-polite society. Many folks are just 'in it for themselves' and could give two hoots about those around them, or in your case, directly behind them.

To directly respond to your question: their behavior was rude, inconsiderate and intolerable. I could tolerate someone standing after a goal is scored --- maybe for a shootout or something real special, like the 'unleash the fury'. You may have to stand up yourselves, which will make those behind you angry, and in-turn maybe someone will tell the original offenders to 'sit down'. The only time I stand up while the puck is in play is when there is a breakaway. That’s it. Any other time please stay in seat.

From a Baseball article:

There’s nothing like watching a base runner steamroll around third in the bottom of the fifth trying to leg out an inside-the-park home run and seeing nothing but crack. I’m not talking about the echoing crack of a speeding ball popping the catcher’s mitt; I’m talking about the crack of the dude in front of you jumping up like a whack-a-mole just as the violent runner-catcher collision happens.

Standing up to watch a possible scoring play develop is understandable, but only if it’s in the top or bottom of the ninth and your team needs the run. Understand I’m not discouraging standing up all together, but standing up during a live play anytime earlier than the ninth is a no-no.

It is hoped that all spectators and FIRST participants strive to be courteous and permitting others to see what they are at an event to view seems a basic courtesy. Standing when your team or a match score is announced, but not during the match itself, seems a reasonable compromise.

Edit: Please forgive my shouting; I'm very visual & tend to make specific thoughts bold in my lengthy posts. (Yes, another etiquette issue!)