General

If it happens naturally there's nothing wrong with that, although it can be unpleasant if the burp or fart smells a lot. Doing it on purpose is silly though. I have a friend that used to fart on purpose loads of times. One day though he completely backfired into his underwear, I told him it served him right and that he should save it for the toilet. Me and my other friend couldn't stop laughing when it happenned.

It all depends of what kind of a place it happen.
If do that somewhere in a theater with a good acoustic during silently pause - it's one reaction ..don't know maybe you'll get some ovations after lol
If somewhere in a pub during England - Ukraine match tomorrow, trust me nobody cares ..nobody even notice it

But perhaps the lack of manners doesn't mean she has a minimum of self-respect?..