another key in shipping them is the anti-static bag, which is just as important as bubble wrap.

I can understand a laptop dropping from 4 feet and not damaging the hard drive. That is if it is off at the time or the computer has something similar to ThinkPad's active hard drive protection. The biggest problem when dropping a computer when it is on is the needle damaging the discs on impact.

Think of an record player, if you drop a closed record player with a record in it. While they were well before my time, the likely damage point is the reader thingie what ever it is called.