this has a 2/2 success rate for me. it probably also works at other restaurants. i always thought it was some legal requirement for places that sell food to provide water, but apparently that's just for venues licensed to sell alcohol, at least in australia. i also thought they'd only give it to you in a cup, but it seems that is not the case. it turns out asking for things can work pretty well sometimes even if they're not advertised as things you can ask for.