Windshield washer OK for winterizing waterlines?

LOL, someone working at the Walmart of Canada said to use Wiper Juice in water lines?
It's good you came here to ask then, if there was any real question in your mind.

What may have happened was the "clerk" was referring to drain lines/P traps, not freshwater lines.
I've used Wiper juice interchangeably with RV antifreeze for years for drain lines in the camper, winterizing a home and winterizing fresh water ballast pumps and tanks in my boat. Works fine for that.