Agreed, this will probably get merged. But I do tip the bartenders in the UC. As a nearly lifelong hospitality employee, it's in my bones to do so. That said, you are correct that they don't get paid the same way as a restaurant bartender would, but you also don't get the bartending skills that you would get in a restaurant when you're in the lounge. My last moonlighting bartending gig I had, I averaged probably $55/hr. I'm sure the bartenders at the UCs are making $20 at most. Anything outside of a vodka tonic is often too complicated for the lounge bartenders, so when I actually find one that knows how to bartend, I'm inclined to tip more than a simple $1/$2 per drink.

I wouldn't tip someone that merely points the way to the shower, however.