Question: We have quite a few [questions on tipping in the USA](https://travel.stackexchange.com/questions/tagged/tipping+usa), but looking through I can't seem to spot one that covers this.

When in the USA, if you are somewhere where drinks are free but served to you, is it expected to tip the person pouring / bringing the drink, and if so, how much?

Additionally, does it vary by location / setting? For example, might an airport / hotel lounge differ from an all-inclusive hotel / resort?

(I'm currently in an airline lounge at a US airport, and was given some vouchers for free drinks when I entered, which are given to the barstaff in exchange for drinks. Some people seem to give a tip, some not. A few weeks ago I was in a hotel lounge which had free drinks for an hour in the evening, with a member of staff removing beers from the fridge and opening them for you, but I was the only one there then so didn't have anyone to copy....)

Answer: 
In general, if you're in a place that also *sells* drinks and you're using vouchers, etc then tip as you would if you'd paid. So a dollar or two per drink depending on price and place. Same goes for discounts and other freebies like a 2 for 1 deal -- although you could choose to tip more up front. Obviously if the staff just decide to give you a freebie then tip on that too and generously (since you just got a free drink). 

Otherwise, if the staff rely on tips, they lose out because someone has scored some vouchers or something. 

For all-inclusive, I'd follow the same rules as you would at a similar non-inclusive resort in the same country. Unless it explicitly says somewhere that tips are not expected / are included. 

In the free hour at the hotel lounge it's more tricky. Again if it's a normal bar and a bartender then tip as normal (or tip all at once up front or at the end). If it's just a hotel employee occasionally fetching you a drink I wouldn't think tipping is expected. But it's probably appreciated so maybe leave them something at the end of the hour.
"It depends."

Typically, the rule is that whoever gets the bill does the tipping. For example, at a catered event, you wouldn't try to tip the people bringing you your food or drinks because you're not paying the bill. I think any time you aren't paying a bill, you're safe to err on the side of "no tipping".

I have been to company catered events at hotels, though, where some hotel employee was manning a drinks booth, with the company covering the cost of the drinks, but the employee had a tip jar out. Not everyone simply carries loose dollars around with them, so I don't think tips are really expected in this situation but tossing a dollar in the jar if you have one is "a nice gesture", I suppose to acknowledge that they are serving you, being attentive, and that this is somewhat outside of their normal hotel duties, and that most likely the bill for the event is not going to have a "tips" line on it.

This is an example where to some extent the onus is on the employee to have a tip jar if they expect tips because otherwise no one is even getting their wallets out. You'll see this sort of thing sometimes with live music too. Should you tip the band? The band itself will usually indicate this by having a tip jar out, or not. If the venue is paying (especially through a cover charge or ticket sales) then there's usually no tip jar because the band is fully paid. If someone expects tips in a questionable situation, see if they have a tip jar, likely placed where you can't miss it, with money in there already to give people the hint.