He's right--that is theft.
Same with the dudes who say they tip or tip extra when bartenders "comp" them free drinks. They then tip the price of the drink, lol... so all that really ended up happening is the customer paid for the drink, the bartender pocketed the cash and the bar owner got the shaft. That's a clear example of theft. And the aggressive tippers that so proudly talk about this are eagerly and actively participants of the theft. So much for their moral high ground...
You me "she", that's ok.
Anyway, the theft though is the bartender, NOT the customer and you don't always pay the full price for the drink like for example, let's say the bartender gives me a $7 margarita free, giving them $3 or $4 extra dollars isn't paying for the drink completely, almost like half-price and the bartender is the person responsible for ringing the FULL price up in the register, NOT the customer. The customer paid what bill they were given and they can't force the bartender to ring up the correct item.
Also, it's not my job as the customer to tell my bartender or server they didn't charge me for something nor is it my job if they overcharged me as well. That's the job of the server or bartender to do things correctly like that. If there is an underringing going on purpose or even not on purpose as the customer it's not stealing to not tell the bartender or server, because we aren't the ones underringing the items in the computer or register, they are. If the server or bartender wants a good tip, if I am undercharged they won't inconvenience me with fixing it, if anything, they should comp something for my inconvenience from the manager or if not the manager out of their own pocket a coke off the bill or something like that if they are going to make me be held hostage fixing the bill whether it's an undercharge or an overcharge. It's not my doing. It's THEIR doing and it's *THEIR* theft or if it's done not on purpose like if they forgot to put something on the bill or they overcharged me by accident, that's not on me, that's on THEM. I am not the person that is supposed to baby-sit them on their every move if they do the job correctly or not. It's not theft on my account, it's theft on *THEIR* account whether it's underringing for the restaurant or overcharging on the customer if it's on purpose. If it's by accident, well it's not theft, it's a mistake, but it's not theft on the customer if they notice they haven't been charged for something, because that's not our job to tell them. I just leave more when I am not charged. If I had to be inconvenienced, they would get stiffed, so I think they'd rather have a good tip and if they figure it out, they can pay it out of at least part of the tip we gave if it's not the full amount of the drink or they may not notice it at all, not my issue, that's theirs. They work there and I am not going to be unhappy in my service because they messed up. If I have to wait there for an undercharge when we have had many overcharges over the years we waited to get fixed, I would be LIVID, even with a comp, my time is worth more than that and I am NOT going to sit there waiting for the server or bartender to fix the check for an undercharge, it ain't happening. I leave a bit more(unless the service was very horrible) and move on. They may not notice it, I don't care. Not my issue. I am not there to be inconvenienced. If they want a good tip, they have to provide good service and if I have to wait to leave, I am not getting good service. It's not theft on our account, it's theft on the server's or bartender's account unless it is unintentionally, even though, not theft on our account if something is not on the bill or under priced.