My old riding buddy had a friend that would do this^^. It wasn't a flattering story.
My buddy managed to do this, when I visited last summer. We pooled the dinner money, I added the tip, he took the money and paid, $8 left over, he comes out and asked why I overpaid the bill, I told him it was the tip. He got that "I'm a dumbass" look, went back in and tipped the waitress.