it should not be allowed for adults to walk around completely naked
Was she walking around though? Or was she very briefly naked whole she pulled on underwear beside the locker because the family changing rooms were taken up by kids big enough to change with their Dad in the men's?!
Was she supposed to wait, wet and cold for a cubicle to become available?
Most naked people I see in changing rooms are naked for seconds. They are usually in one spot, close to their clothes. I have yet to see willys or boobs waving about as the owners strut around deliberately showing themselves off to young members of the opposite sex!!
If your lads don't want to risk the chance of seeing a naked, or seminaked female body after a swim, or shower they should probably stick to only using the men's changing areas.
If they briefly saw a naked man in the men's area, would that be a problem?
I used to faff around trying to cover my modesty with a towel one handed, whilst trying to pull my knickers up my not completely dry legs, one handed. Now I don't bother. I drop the towel to my waist and put on my bra. Once my bra is on I drop the towel completely and put on my knickers. I'm usually sitting at this point!
There is always a chance of seeing nudity in a changing area. So long as nobody is strutting, or shaking, or jiggling, or whatever else what's the problem. It lasts seconds. People want to get dressed pretty quickly because it gets cold!!