Originally Posted by SingaporeJoe

Let's say you harvest someone else's connection and use that to piggyback to the service he/she paid for.

Or you crack the service and read the communication of someone else on the plane.

It's not necessarily very secure. Don't think we have conclusive evidence, but there are serious concerns:
http://www.sniffwifi.com/2011/03/get-personal-gogo.html

Under which country's jurisdiction would that be handled? The forensics would definitely be interesting, not mentioning the questions of liability.