The messages have your seat number on them, and the cabin crew has the name of every passenger on the manifest by seat, so what kind of numb-nuts do you have to be to think your messages can't be traced back to you? I suspect the Virgin programmers thought passengers would be smart enough to understand this and thus refrain from being dicks on a plane.
“ Dicks on a plane “, a worthy sequel to “ snakes on a plane “. Featuring p&ssed up charter passengers off to Zakinthos from your local airport.