It's dishonest to run out on a bill.
Frank is eating a meal at a popular new restaurant when he realizes that he left his wallet at home.
Frank wants to avoid getting in trouble for not having money for the check.
Frank calls a friend who lives near by to come and loan him money for the check.
Frank pretends to go to the bathroom then slip out the back entrance.
Frank avoids embarrassment and is able to enjoy the rest of his meal.
Frank is humiliated at work the next day when another patron who witnessed his dine and dash turns out to be a coworker.