In European bars or nightclubs, if (relatively) attractive girls ask strangers for drinks or dishes, then it typically means they are doing it professionally.

There is even a special phrase "consume girl" meaning that the girl's job is to lure clueless customers into buying expensive drinks for them for a cut of the profit. The surest sign of being a "consume girl" is that they typically don't consume what they ask for.

It's all about money, and has nothing to do with social games, whatsoever. They are not spoiled brats, but trained for this job.

I am not sure how common is this "profession" in the US, but in Europe it's relatively common.