No, just very very desperate. I guess they think that there's plenty of space in there and that once the wheels go up, they can just hop off onto a convenient ledge and sit there for the duration of the journey and remain perched there once the doors open and the wheels are lowered on final approach (note, the wheels don't drop at 40,000ft) before jumping off once the plane stops. In reality, they're probably crushed to death straight away when the wheels are raised and they drop like a sack of excrement when the wheels are lowered. If they're not crushed to death then they'll be in absolute agony until they either suffocate or die of hypothermia once the aircraft reaches altitude.However somebody thinking they can do the equivalent of surviving at the peak of Everest for 6hrs, followed by a parachute-less descent to earth from 40,000ft is undoubtably a few sandwiches short of a picnic.
Whichever way, they're nasty ways to go and I wouldn't wish that on anyone.

I'm not being nasty for the sake of it...