Eh, perhaps "tasteful" was the wrong word. I'm very anti-tipping overall (though will hold my nose and tip where appropriate, because that's just how things are), but I think, in a place where tips are expected, a tip jar is fine, as long as it's fairly unobtrusive and not in your face, and not verbally mentioned. Of course, until now, Uber was not a place where tipping was expected, so... sigh.