It stays on pretty well, actually. I accidentally banged in on the wall as I set it up, which peeled off a little bit on the back corner, but no amount of rubbing with my fingers does any damage.
I also tested the spray on a spare mouse. Using matte Krylon Fusion as an undercoat makes the Plasti-Dip stick like it's part of the plastic. Impossible to chip off. I want to be able to peel the stuff off of the board later, so I opted to avoid this step.