If there is no risk of a power failure, you're in good shape.

For me however, the small cost of winterizing removes all concern about any
unexpected troubles that could cause a frozen and cracked block.

Have you checked the lower unit grease/oil ? All it takes is a short length
of fishing line to ruin the seals and water gets in the unit, followed by an
expensive frozen and cracked lower unit housing or rusty bearings and gears.

Don Dando