So what you are saying is that if you stiffed the waiter, but then they asked you about it you would then tip? I'm not even sure that there is much difference between confronting and inquiring.
At most places I’m out the door before they would even have a chance to see what the tip was. So I guess they would just need to chase me down in the parking lot to inquire why they got stiffed.
The difference is in attitude! If they are yelling at you or trying to blame it on the kithcen staff, there is no way that they will earn back their tip. If they are polite and inquire if there was anything that was not as expected, they might earn it back.
And yes, I have been chased down in the parking lot! That is crossing all lines! Will never go back!
I think a lot of people see tips as a right. They are a privilege and are 100% based upon the customer's satisfaction!