Arved, the glass used in camera lenses is nothing like regular glass, it is soft and easily damaged (coatings as well, that may be what is easily damaged). There have always been special cleaning solutions and cloths for camera lenses. People have mentioned that windshields are getting softer, you may be right that they have some anti-laceration coating on them (years ago GM was selling cars that had a soft layer on the inside that was supposed to reduce laceration in the case of accidents, but it would get scratched, messed up from removal of inspection stickers, etc., I think they only sold them for a year or two). But I still think that glass is harder than paint...it's just not harder than sand and rock grit from the road...so once you scratch the glass, it's almost impossible to polish anything out.