yes, i'm curious about that potential damage thing too.
I've been doing it for years, as long as you place the blocks correctly underneath the outside channel there is nothing to damage.

The only possible thing that could happen that might cause damage to something would be if the tech ran the motors wide open with no load on them, then the armature windings might separate from the high rpm's but that would only be because the tech was just inexperienced ignorant to the fact that could happen.

otherwise there is nothing to damage