I worked for an electronics resaech company, often designing components that would be flown in satellites. The amount of vibration and shock testing that has to be done to ensure they (and the satellite) would withstand the launch is consideable, and expensive. A quick and easy way to find out if such a component was robust enough, before it was properly tested, was to post it to ourselves by Royal Mail. If it survived, it was robust enough to proceed with the rigorous shock and vibration tests.