I'm assuming the electric motor on a hard drive is brushless due to the long hours and rpm the brush would have to sustain. So breaking in the electric motor to "seat" the brushes seems redundant.
Bearings on the other hand can be burned in
It doesn't hurt to run my computer HD for a few days does it? The centrifugal force helps flatten the platters and the hard drive becomes accustomed to the heat.
Anyone work at a hard drive company and break in hard drives for a living? I'm sure they just don't assemble and sell... And I figure manufacturers don't want to spend a whole lot of time testing their hard drives. (if they did there wouldn't be so many immediate rmas)