Three lawyers and three accountants got on the train in New York to go to a convention in DC. The three accountants bought a ticket each, but the three lawyers bought only one ticket between them. The accountants commented on the illegality of their action but the lawyers said, "Trust us--we're lawyers."
When the conductor entered the end of the car to collect the tickets, the three lawyers got up and all went into the bathroom together. When the conductor knocked on the bathroom door, a hand shot out with the one ticket, which the conductor duly cancelled.

On returning to their seats the three accountants expressed admiration for such a clever trick. "Well," they said modestly, "we ARE lawyers."

After the convention they all entered Union Station for the return trip home to New York. This time the accountants bought one ticket between them, while the lawyers did not buy any tickets at all. The accountants were amazed and said so. "Trust us," the three said. "We're lawyers."

When the conductor arrived, the three accountants quickly jumped up and went into the bathroom. As soon as the door closed, the three lawyers got up and headed for the ajoining bathroom. As the last lawyer went by the accountant's bathroom, he knocked on the door. A hand shot out with the ticket, which the lawyer quickly grabbed before entering the other bathroom.