My DD (who was two in July) started swimming lessons this morning. (It's in a gym complex, if it makes a difference) It was a small class of about five other two year olds. The rule of the gym is that all children under 3 years old have to wear a swim nappy. I didn't think this was unreasonable, likely some two year olds won't be potty trained and to prevent accidents etc. in the pool they want them all in nappys. So as I'm putting my DD in her nappy and swimming costume in the changing room, another Mum that I vaguely know comes and asks what I'm doing, and that she thought DD was potty trained, (which she is). I explained the rule and she said that she already knew but her DS was potty trained (but still two) and she thought it was a ridiculous rule and wasn't going to do it. I kind of ignored it and took my DD through but then the other mum kicks up a right fuss with the swimming teacher, screaming and swearing and ended up storming out of the pool with her poor DS! Is she a CF? Or is the rule unreasonable?