Its clearly a try on Nathan and to be fair as wfp users given law of averages its something that may cross all our paths at some stage.
While it is not impossible we could scratch glass its highly improbable and unlikely. As im sure we all can testify to there are scratches on an awful of glass out there.
In my opinion mostly its caused by diy merchants or after over building work where paint, plaster and silicone etc splatter the glass.....