I've always been told not to and lived by the advice you shouldn't hit on waitresses and bartenders.

I've had up to 3 sitting at my table with me while they are working, compliment what I'm wearing, I've had them give me free drinks, showing me their tits, hugging me.. Are they just trying to sell drinks or are these women actually interested?

If it changes anything I'm usually at the bar by myself when this sort of stuff happens.