You can ask people to fill them in any cafe and they (in my experience) will always oblige ... I'd probably always be buying something when I ask though, maybe they wouldn't be as obliging if I wasn't.are there many public places where water bottles can be refilled though?
I piss in bar toilets and fast food toilets all the time without buying anything, fwiw. If it's small place I'll usually ask, don't bother if the place is big and/or busy