Ok well I just find it funny how rain water is so impure yet people turn around and run hose water across their car which most likely has impurities not only from the water but particles from the rubber on the hose as well as dirt and bugs that get up in the hose while it sits for however long not in use.

Now if you had said something like the dirt that is on the truck is not cleaned off, and the wiping motion is only taking those particles of dirt and causing tiny scratches like real fine sandpaper...then I would have agreed