I think it's a matter of mutual respect. I can understand a woman's need to do that and not wanting to hide in some smelly washroom to do it but I can also understand that she should be considerate of others. There are some women who think it is her right to whip out her udder and let Junior start sucking like Romulus and Remus, everyone be damned. I think that is an inconsiderate attitude and I don't agree with that degree of openess and the expectation that everyone else conform their behavior and attitude to hers. However, if a woman is trying to be subtle and not being too overt about it then I would just turn away and let her do her thing.
It's like blowing your nose or sneezing. If you just let fly with the snot and honk like a goose then people will think it's gross. But if you try to be considerate about it and politely do your thing, then that's cool.
Aw what the heck, just show me the titties.