When a designated driver says he will bring every one home from the bar, and then precedes to drink himself into a vomiting stupor. So that it is obvious he is the only one who can't drive.
I told my uncle's to come to the bar with me, and that I would bring them home. I then did 4 car bombs, 2 shots of vodka, 6 beers, and 2 martini's. My uncle's claimed I pulled a bait and switch on them.