On one occasion, someone came up to me and tested my reg and bc inflator while I was wearing my gear without even asking me -- like some dive masters do with inexperienced tourists at resorts.
Yes, it happens a lot, and in fact this exact thing actually happened to me last month. IMO, it's entirely different from carrying heavy gear, pulling out a chair, or opening a door for a woman, which are simple courtesies. This checking of the inflator or testing a reg or tugging at releases is supervisory in nature rather than courteous, and any guy that can't understand this needs to think about it a bit more. If you can't imagine a guy reaching over to another guy who is not his dive buddy and without being asked checking an inflator or tugging on releases, then why on earth would it be okay to do so with a woman who just happens to be on the same boat?
In my case last month, I was part of a tech sidemount instructor course, and in the process of performing a head-to-toe pre-dive check, my assigned buddy for the dive reached out and inflated my wing. This was already our third day of the course (and keep in mind that this was a tech-level course and was an instructor-development course on top of that), and by this point those guys should have got the message not to touch me and not to swoop in to "correct" my placement of bungies on the tanks, etc., but nevertheless he did reach over and test my inflator. I snapped at him, "Don't touch. When you do a head-to-toe you may comment or ask but you may not touch another diver's gear without permission!" He was offended and rolled his eyes, but by that point I didn't care. Gentle requests, joking explanations, "thanks-but-I'm-okay" delivered with a smile, none of it worked with this guy. The only message some men can understand is a slap down. This same guy had earlier physically snatched a cam band out of my hands to rethread the buckle when I was working on it after having slipped a weight on it. I'm sure he would claim he was only being "helpful," but I saw it as interference. He could easily have said, "Would you like me to rethread that for you?" or while doing the pre-dive check, "Is your inflater connected properly?" Moral #1 of the story: when dealing with a jerk, be direct. Moral #2, and a point I brought up with the other candidates in our debrief, even if you're dealing with learners or inexperienced divers, you do them no favors by being overly solicitous--in fact, you hinder their development of self-sufficiency. If you think they need to correct some gear issue, tell them what you've noticed and let them sort it out, or at most tell them and offer to sort it out for them.
Keep your paws to yourself.