I'd place my bet on "he was squished by the landing gear". Ain't much extra space in there. Damn stupid idea. But a good point about "if a fool can sneak in there to stowaway, why couldn't a different fool sneak a bomb in there?"

Our air travel system here in the US is wide open to attacks, ain't nothing can be done about it, really. They just inconvenience us travelers because they can, and we're easy targets all in one place. Makes the TSA look like they're doing something.

Who steals out of our baggage?
Baggage handlers.
Who puts our baggage on the planes?
Baggage handlers.
Who could most easily plant a bomb in a bag and put it on a plane?
Hmmm, let's see.....