i cant imagine bartenders in airline lounges are actually paid in the standard server/bartender manner.

they must be paid a normal hourly rate otherwise who in their right mind would work in a lounge given how many "free" drinks are provided and the large international feed which of course do not tip, especially in a lounge where something is provided for free.

while i am an american, i gave up tipping ages ago on a premium drink chit because i pretty much only drink wine and im sorry--if i were in a flagship lounge, i would pour my own drink--and i do not need to tip someone 2$ to pour something into a glass for me.