Corrosion as such is probably not the issue unless the aircraft is parked outside near the sea.
Pace - I am not sure I would agree. I know a great deal more about auto engines than aero engines (well in terms of what they look like inside). It is surprising how quickly surface corrosion sets in if the engine isnt used and the damage this can cause. Personally I would want to see an engine used at least once a month, and I dont mean just a ground start which potentially would do more harm than good.