Jealousy factor

A customer who knows she's on a three drink limit taught the bar a new lesson in self-discipline/policing. She walked into the room last week with, I'm guessing, a four bar head-start. She ordered her first drink and pre-paid for the next two. She then counted out $40 in cash and put her remaining money, credit cards and license into a self-addressed, stamped envelope. While I was mixing the first cocktail she excused herself to post the envelope at the mailbox on the corner. She returned to her waiting drink, smiled and said without irony, "Nothing bad can happen now."