good question, and some good posts (TNT as usual of course). I train in a college gym and it often overcrowded. This and the fact that the management does a poor job of organization leads to a mess. Sometimes its not so bad, sometimes there will be 5 open squat racks but no clips to hold the weights on the bar because someone stole them to use on preacher curls (probably because someone stole theirs as well.) So i hear ya man.

On a related note> I ran into a guy the other day who I had never seen at the gym before. He was talking to someone between spotting sets for his buddy. I needed to borrow a 10lb plate from his station (which by the way had like 4 or 5 10lb plates) so I walk over and reach for the plate and say "hey, do you care if i steal this from yall for a few mins?" and the guy stares at me blankly and half nods his head as to say "how dare you talk to me". He was about 2 inches taller than me and maybe 190 lbs by rough estimate... not sure where is getting his attitude from. I just grinned and said "thanks !" and walked by to my station. Just as TNT said, being nice is the way to go regardless of how ignorant and rude the poor guy is, in fact being nice can almost be like a legal slap in the face because they have nothing to fuel the fight with when you are being nice to them.

This doesn't answer your question about etiquette though, sorry.