You shouldn't take advantage of people who are drunk.
Peter is out at a bar with his friend Fred who has gotten very drunk.
Peter wants to take a taxi home.
Peter orders a taxi for the two of them and pays for it himself.
Peter gets Fred to order and pay for the taxi because Fred is very generous when drunk.
Fred and Peter both make it home safely and neither has spent more than they remember.
Fred is confused when he sees the taxi charges after he sobers up and blames Peter.