I've had the classic scenario happen where me and my wife were grilling outside during the summer and one of her friends was out there with us for probably over an hour - talking, eating, just hanging out - wearing nothing but jean shorts and a moderately revealing bikini top that showed off most of her breasts above the nipple, her belly and her entire back as if she might as well have been topless whenever she turned around. It's kind of funny; I don't think she ever in a million years would have hung out for an hour in front of her friend's husband in a not-particularly-concealed yard in jean shorts and a BRA (even a bra that concealed more than what she was wearing)... but the fact that the thing in the exact shape as a bra happened to be made of this different, water-resistant material makes it totally fine.
Not that I'm complaining, of course!