I have a friend that I dine with monthly that actually works throughout the meal to find a reason NOT to tip the waiter.
One time she insisted the waiter didn’t seem friendly enough and last week she had the audacity to not want to tip because the waiter didn’t ask her a second time if she wanted an appetizer.
As a co-diner, I’m always conflicted: Do I pay my share of the tip and move on or do I pay for her share?
Evaluate The Situation
The first step is to evaluate the situation–is your friend justified in not tipping properly? If yes, then let him/her tip what they believe is appropriate. If they ask your opinion, then suggest they tip SOMETHING, as little as it may be.
The First Time
If it’s your first time out and your friend tries to stiff the waiter, then cover their tip.
It’s unfair to you, but it’s even more unfair to the waiter who worked hard to make sure your meal was good.
If your friend seeks your input, diplomatically share that you felt the service was adequate and worthy of at least 10%.
After the first time, it’s not YOUR obligation to cover your friend’s tip.
His/her cheapness is unfortunate, but make sure you tip well. If it’s in your budget and you’re feeling generous, then add in an extra dollar or two.
Even if you choose to pay your share and let your friend stiff the waiter, it’s embarrassing to dine with someone THAT cheap.
I personally know I’ve bolted out of restaurants as fast as I could so that I wouldn’t feel humiliated for my friend’s cheapness or worse–be mistaken for the cheap tipper.