I can't find the article you are talking about. But I have an expectation of privacy in locker rooms. That's why they are separated from the main lounge. That's why men and women get separate ones. Because people value their privacy when they dress/undress. So I don't appreciate it when people of all ages congregate in a locker room where people of the opposite gender are trying to change. It's inappropriate, and it's rude to intrude on people this way. Some people are more relaxed about nudity; good for them. That doesn't apply to me, and I still want my privacy.
Obviously, very young children need assistance with changing, so they need to be with a parent/caretaker even if that puts them in the "wrong" locker room. No one really cares what young children see anyway. (By this I mean 6 years old max. Six-year-olds should be able to do everything by themselves.) But older children don't belong there. If they have special needs or safety concerns, then they should be using the family room. If there isn't a family room, they need to use a privacy curtain or a restroom stall. If none of these are available, then I suppose the adult could go in first and give everyone a "heads up" so they can hurry or wait to undress. Just barging in with your older kid because you're comfortable with nudity, or scared to let him out of your sight, or want to chat the whole time you apply makeup... rude.
