Dh has an awful story about this. He was at a conference type thing, and arranged to have dinner with some of the people on it.
He actually arrived late, having had dinner already, and only ordered a coke and a coffee. Come bill time, he was included in the whole thing. Being timid, he paid a whole share.
But, get this, the woman who'd done the calculating had messed up, and they'd all paid too much. She made a great show of 'oh, we'll all go to a bar now and this can be the kitty'.
They head off to the bar, order, and then she gets a phone call, and leaves saying 'I'm off to meet up with some friends'. Taking the kitty with her!!!!!