The One Pass Water Blade is perfectly safe for all paints and clear coats as long as they are CLEAN! You must wash your car and give it a good rinse before you 'blade off the water. Our silicone T-Bar and Y-Bar edges have less friction than a towel, but we can't say the same for anything that may be on the paint.
True story, we actually had someone that used a Water Blade to remove mud from their car without washing it first. As you can imagine, the 'Blade did a terrific job of dragging mud across their paint. This did not work out so well for the paint.
Don't do it!