Gym etiquette
As an older 'lifter who has trained in gyms all over the country I learned early on, at a body weight of 160 lbs, that one needn't be a rocket scientist to respectfully ask whoever is in the area if you may take some weights, particularly when they're 100 lbs bigger.
As I got older and much bigger I found pissing on equipment like a wolf to mark my territory established me as the alpha male in one gym but got me tossed out of a couple others. And the wolf method leaves a bad smell.
I find it quite rude for people to come over and help themselves to plates in my territory, particularly knuckleheads with ear phones on. I do not like to raise my voice so I just tap them in the head with a handy 5 or 10 lb plate. That invariably gets their attention, they get a short lecture on gym courtesy and directions to the ice, for the lump on their head.
Interestingly enough, I've found that if I am lifting heavy other folks in the gym tend to give me extra space and respect. But not always. I once had a small woman get quite irate when I wouldn't let her work in on the leg press. I had 1000 lbs on it and she wanted me to unload it between sets so she could finish her gruelling workout doing a couple of 20 rep sets with a 35lb plate on each side. I told her to "piss off" and she went to the manager of this particular 24 hr Funkiness. He took one look at the weight and told her to leave me alone and do something else.
Seriously: The weight room is a very dangerous place. Two things most "health clubs" never do is teach gym etiquette, like wiping down the equipment between sets and when finished, asking before taking weights, no head sets (can't hear "Look out!" or "Get the fuck off my foot"), and putting their weights away.
I am welcomed at numerous facilities both because of my background as a successful strength coach, (numerous Olympic athletes and National Champion Weightlifters) and the fact that I will not allow any unsafe activity I see in the gym. Gym managers appreciate this because they don't want to be sued.
At 6'1" and 275 lbs. I don't have to demand respect in the gym and have found, to my amazment, that I intimidate neewbies when training heavy, so in actuallity, I correct improper behavior in a diplomatic, respectful manner using low tones and soft language. I respect anyone who shows up at the gym to do something, rather than sit on their fat ass watching the usual crap on TV, and there is rarely any need to intimidate or threaten. Usually they don't know any better and appreciate being informed in a nice way. I know I didn't know squat when I started.
When I come across someone with a sincere desire to get fit (like prep or college athletes) I will interrupt my training give free training guidence in order to get them off to a proper start. After all, I'm a coach. It's what I do...but before I could coach I had to be coached. Take a little time to pass on your experience, isn't that how you got where you are? Play it back...watching people improve under your tutelage is very gratifying.
Knowledge is power, share the power.
Ubercoach
On a couple of occasions I have run into bodybuilders doing esoteric super set routines requiring them to tie up several pieces of equipment simutaneously. They usually require a 25 lb. plate to get their attention. They do not want to share and they do not play well with others. Once I have their attention they are referred to the local steroid palace.