From today's "We're investing in your United Club experience" e-mail:
Expanded beverage program
We're adding to our portfolio of premium beverage products available for purchase, while maintaining a selection of complimentary beer, spirits and wines at our U.S. United Club locations. Beginning September 10, be sure to try regional and local favorites as well as other new items from our expanded beverage menu.
I interpret "maintaining
a selection of complimentary beer, spirits and wines" to mean the cheapest they can find.