If I put the title I wanted to put here, it would give the punchline away.
Up jumps one of his students. "I'm a smuggler!" he declares.
"No!" shouts another. "I'm a smuggler!"
By this time, third and fourth prisoners had joined in: "WE are smugglers!!" - all vying for the all-important title.
A Spartacus moment. No need to wonder why they were incarcerated.