Locker room etiquette

Jman had a field trip at daycare today, so I had just enough time to go to the local YMCA to work out before I had to pick him up. As I was coming from work, I had to get changed completely once I was there. I walked into the woman's locker room, started to get changed, and noticed that there were several children in there as well. There were 3 girls and 2 boys...boys that appeared to be older than the "5 or younger" age limit which is allowed in the woman's locker room.
So, I asked them how old they were and one of the girl's told me that the boy's were 5 and 10 years old, and that their mother was getting changed (on the "wet" side of the locker room). I mentioned that they should let their mother know that they were too old for this locker room, but that there was a family locker room they could use.
I was waiting, and waiting for the mother to come out, since I was not going to get undressed in front of a prepubescent boy. The mother finally came out (she was not finished changing), and I started to mention to her that there is a family changing room right next to this one, since the boys were too old to be in here. She interrupts me to tell me she speaks English..OK...I again say there is the family dressing room next door...she interrupts again to tell me she can read English. Great, if only she could understand it and follow the rules. As I try to continue to talk to her, and ask her to have her son go at least go into the closed off area so he is not staring at everyone.. she goes off on me. She tells me I can change in the toilet stalls...no I don't think so. I mention again the family dressing room. She has the audacity to say that she does not want get undressed in from of him, and that is the way the room is set up . What? So it is OK for me to get undressed in front of him? I finally have had enough and go to get one of the staff.
At the same time, I run into another friend of mine. So, the staff member gets ahead of me a bit as I'm explaining to my friend that she may not wish to get changed into her swimwear just yet since the dressing room has some older boys in there.
I walk in and hear the staff member explaining the rules to this woman. The woman starts saying how she does not want to leave them alone while she gets changed, but obviously "she", meaning me, "who doesn't have children wouldn't understand". I replied, I do have a child, and he's a boy too. The staff member, who was quicker to the point, mentioned that the YMCA offers daycare (free) for this purpose. The woman makes a snide comment that she'll be sure to keep the boys out when "that woman" is in here. The staff member responded with, "well, it is all the time...they are not allowed in here at all".
It's funny, I probably would not have involved the staff if the woman had just acknowledged that I had a right to feel uncomfortable with her 10 year old boy in the locker room. If she had said something like"I didn't realize anyone else was in here..." or "I didn't know there was a family room" or "let me gather our stuff, we're all done here". Instead, she wanted to insist that she didn't have to follow the rules and she thought that if she confronted me I would back down. I don't think so. The rules (which, by the way, are printed in big letters on a placard in the locker room) are there for a reason.