Any Damage Reports of Incorrect Winterizing?

LOL.. Yes, every year. Toilet valves, water pumps and pump filter housings, outside showers.. It happens.

That is why I always use RV antifreeze, even if I do blow out the lines with air first. It gets the residual water out of the pump, lines, and valves.

Me too!  .........Blow out lines, add antifreeze.

The first thing I do is drain the water heater. AND the low point drains. Hard to use compressed air with 6 gals of water, antifreeze or not. Good lesson.

I do not blow out my lines, instead I drain everything including the low point drains, turn on the pump to make sure its not pumping anymore water, add antifreeze to my freshwater tank and turn on the water pump, then open each water valve on each hot/cold sink valves, shower valves, and run toilet a few times until I see pink antifreeze coming out, I add a little antifreeze into the toilet bowl also. Don't forget the shower on the outside of the pod. I do close the bypass valves and drain WH. Never had a problem doing it this way but takes a bit more antifreeze since you need a bit more for the pump to start pumping it though the system.