For some babies, a quick bf is a way of calming down, of making contact, of reliving anxiety.
To get out of the pool, feed for a short time (eg a minute or so) and then get back in again is an option, but it's one every mother who has this parenting 'tool' can choose to do wherever she happens to be.
It is the law.
There is no hygiene risk. The milk is going into the baby, so the idea that anyone else would be swimming in someone's else's breastmilk is daft - she might leak a bit, but she might leak without feeding, and unless you are going to ban lactating women, we have to live with that and accept that when someone leaks we are talking about a teaspoon or so. Big deal. And it's just breastmilk, FFS. It's not going to be seen, touched, or tasted...