This one is pretty awful, and if the person is a poster here, sorry for sharing this story, but it's so apropos.
At Typhoon Lagoon last year, I saw a woman wearing a one piece bathing suit that had a serious problem. When it was dry, it apparently was completely opaque, but when it was wet, it was like seran wrap. The woman was about my grand mother's age, and seemed to be a very nice lady, and people were pointing and laughing, so I felt bad. I went up to her with my towel and whispered that her suit has gone 'clear' in the water, and I put the towel in front of her. She stood perfectly still, and I thought she didn't speak english at first because she looked at me like I was crazy. Then I guess what I had said sank in, and she got this mortified look on her face. I told her that they sell bathing suits here, and that she could keep my towel to head up to the shop.
I just felt so awful for her, but this is the reason I always buy black suits, and I make dern sure they're well-lined. I swear that the 'lined' suits last longer anyway.