firstly -I would have paid out - TBH there is no other way.
While I trust my employee's I can tell you this without a doubt - they would rather Lie/Deny any wrong than fess up - ive had examples of this
I am a bit concerned about your post - I sneakily removed the scraper ? - WHY ? somewhere in all this you must acknowledge the possibility your employee has done this - and then you are presenting a case different to actual events.
One persons point of view is another abusive behaviour...
Its a shame you couldn't go - just to prove in your mind whether it was a scraper/brush or bogus claim - that could only be done by you in person.
Thankfully these things are very rare
I can understand what you mean about employees you can never tell 100% of they are being totally truthful.
The reason why i removed the scraper sneakily is because let be honest. If you look at a Gardiners Plastic Scraper it looks like it could cause scratches. When i first started using them i was reluctant to use it at all, as it just looked like it had potential to do damage! I remember phoning Gardiners and asking them and they said it was perfectly safe to use for scraping. This was donkeys years ago. But what i am trying to say is that if you showed up a customers house and said oh this is the waterfed pole we use, by the way on the back it has a plastic scraper. I feel like you are just asking for them to pass 100% blame that the scraper did the damage, even if it was not used they would still fire blame. That is why i took it off. In my mind i have still never seen scratches be caused by the brush or the Gardiners plastic scraper, but i just didn't want to give the customer the chance for blame, but either way it all backfired didn't it because as i say, they went abusive just from seeing the brush nevermind anything else.
I saw photos of the glass and scratches on them, so that was enough for me to see that it was definitely scratched. There was multiple scratches in lines in 1 small area. Again if my health wasn't absolutely dire i would of gone myself but it's not possible right now.
As you say thankfully these things are rare. Last time we got accused of scratching glass was 4 years ago, and i gave same explanation to the customer as i did this one refused liability and they just accepted it straight away and we still clean their windows to this day lol.