Well, it doesn't really surprise me that someone would ask something like this - the Dbag factor is pretty high in commercial gyms these days.
About two years ago I was training at one of those 24 hour places which you enter with a key card and which rarely have staff around. It is pretty dead and I am doing bent barbell rows at a rack which has a flat bench next to it.
Now, I am usually pretty inattentive to others during my workout - Ipod, hat pulled low, focused on my own shit. I rack my weights, clean my sweat off anything I use, give a spot if asked, but I am not there to make friends, hit on chicks, or do anything but grind out my reps and gtfo.
As I am finishing up my first heavy set of rows I notice this kid on the flat bench sitting up with the bar - loaded with 205lbs - sitting on his hips. He has clearly failed and had to roll it down his torso to get up. Well, once he gets his shit racked again I notice him going for another set. So, I break my normal protocol and offer him a spot. He refuses and acts as if he is insulted that I would dare imply he needed help.
Fuckstick got to roll 205lbs over his ribcage again and that is the last time I have said shit to anyone in a gym other than requesting a spot or "# of sets someone has left."
I spent my college years working as a personal trainer and most guys in a gym have such huge egos - despite shitty performance/physiques - that it isn't worth the effort. And chicks get hit on so often they just default to that assumption.
All that being said, yeah, I would pull a bar off someone. But I also wouldn't be surprised if they gave me the stinkeye for it instead of thanking me.