I've been to the Bank twice - and both times for the open bar. It is a pretty sweet deal ... house liqs + champagne for the ladies from 10-12.
The crowd is a complete mish-mosh of random people that the promoters picked up along the strip. I'd imagine this spot as a pre-party for most ladies to knock back a few free drinks before heading to their real destination.
The last time I was here this midget (legit 4 feet), in a polo and jeans, was walking around the bar begging girls to come to his table for free drinks. He actually said, "Put down that $1 tip and come drink with me!!!!!!!!!!!!!!" Hmm... really difficult decision there :P