Heck, F9 did that for me when the comp'd me elite status last year. One free drink (on a domestic flight, too!) and free TV. I thought it was a nice touch, although I don't know if it's really worth it to try to keep track of where each one of your elite pax is so you can get them their free drink.

Of course, if you did that for 2P and above on UA these days, you'd practically be serving drinks to the whole plane anyways (at least on some flights).