Spinning hard drives have a decent gryoscopic effect. Hold one while it's powered up and try rotating it in a manner that would change the plane of the platters and you will feel the resistance.

Each time you do that, it puts a slight load on the spindle bearings. Do it repeatedly on a varying 5-30 second cycle and you'll simulate what a harddrive on a boat or barge in the open water would experience.

I can imagine that would create additional wear and tear and contribute to an increased failure rate.