This one’s a pet peeve, especially if the person is with me. IMO it’s one of the simplest ways to discover your friend likely has zero game with people who aren’t paid to be nice to them.

ETA: In case you feel called out and are wondering “What, so bartenders and waitstaff are totally off-limits?”
Of course not! You can shoot your shot, just try to keep it holstered until you’re (1) on even footing instead of a customer-host advantage and (2) aren’t cornering them in a place they must stay to make a living. For example, you could hold off until the bill is paid and/or they’re off the clock, then ask for digits on your way out (signaling you have no intention of bothering them further if there’s no interest) or give your number so the ball is fully in their court. Of course, if they shoot their shot first, rules of engagement are suspended. Mine did and she’s alright I guess. The above are her suggestions.