Engineers and Lawyers
Three engineers and three lawyers are traveling to a conference on the train. The lawyers all go and buy a ticket each from the ticket booth. Then just one of the engineers walks up and buys one ticket, and the three of them share the cost.
The lawyers ask, "How is do you expect to get away with that?"
The engineers reply knowingly, "Ah, you will see."
When the ticket inspector starts to come round, the lawyers remain in their seats, but the engineers all lock themselves into a single toilet cubicle. The ticket inspector knocks on the door, it opens, and a hand comes out holding a single ticket. The inspector stamps the ticket and carries on.
A few weeks later they all go to another conference. The lawyers this time decide that they will buy one ticket between them, but the engineers buy no ticket at all.
Again, the lawyers say, "How will you get away with that?"
"Ah, you will see."
When the ticket inspector comes round the lawyers all go and lock themselves in the cubicle. One of the engineers then walks up and knocks on the door.
Of course, any normal person would just buy their own ticket, thus not forcing up prices for everyone else, and have a good kip in their seat.