The lower the voltage and the higher the wattage the thicker the filament, thus the tougher. I have personally dropped on concrete a string of lit mini-bulbs while putting up Xmas tree lights around the house, and they still continued to work. Trucks and cars bounce over rough roads at night with there lights on. Flash lights get dropped and often work afterwards. There is not much mass to the filaments. While in storage the filaments are cold so as to be even tougher. Foam around each bulb should protect them. I suspect the glass might break on some bulbs before the filaments. Best test would be to package some up and drop them from a height of 500 feet or so and see if they survive.
Offered by Mike.