The US or maybe European model you're likely thinking of here probably doesn't apply. A hostess isn't a waitress or a bartender (at least not strictly) her purpose is to get customers to buy her drinks. So getting her number isn't surprising because that's how she'll maintain regular customers.

As a friend once explained it to me, her job is to turn you upside down and shake all the coins out of your pockets, only after a few drinks it can quickly become hundreds of dollars followed by some sober remorse.