WARNING: Do not even think of trying this yourself. If you pull this joke on anyone, you (and the victim) will probably go to jail (and you will hold thousands of travellers up). I shall not be held responsible if you ignore my warning and try this anyways. I cannot stress this enough! Do not try this yourself! Check with the FAA for security and safe travel guidelines in your area.
Needless to say, he never played any mean-spirited practical joke on anyone ever again!
And, the very best part about this one: It's a joke that keeps on giving and giving and giving. Now, every time he flies, he manages to get pulled aside by Airport Security, strip-searched, and interrogated by scary looking Homeland Security Agents for over an hour (usually missing his flight in the process)!