These things happen from time to time. You must be extremely desperate or ignorant to try pulling off a stunt like that. These planes usually fly high enough for the air pressure to drop to lethal levels. If you somehow don't suffocate, the freezing temperature will surely get you sooner or later. Either way, it's pretty much a death sentence.
That is a good point. If the landing gear gets stuck because there a mangled carcass in the mechanism, it’s going to spell bad news for everyone onboard.