I agree on all your major points.
My take on what happened in your video clip is the following:
The individual was embarrassed being called out in front of a large crowd and had to try and save face (no pun intended) by returning a smart comment.
Hind sight being 20/20, perhaps things would have turned out differently if someone had put on their mask, jogged over to her and her friend, and said, "Ma'am, I'd hate for your great day of paintball to be ruined by a direct shot to your face. Please put your mask on. Thanks!".
The delivery method is just as important as the message itself.
For some this may seem too "nice" but if the end result is that she understands the purpose of the rule and the concern of her fellow players, then it was worth the forced consumption of one's pride.