Specifically, I've got a Sinn 103 with a saphire crystal and AR coating on the outside, but short of peoples' first hand experience with that watch, I'd welcome owners of other coated crystals as well.
I've read here about AR coatings scratching, but I'm really not calibrated at all. My 9 day old crystal has already survived a number of light hits. What I'm wondering about concerns a particular application: motorcycling for several hours, with the watch under and in contact with a textile jacket. It's probably nylon; maybe polyurethane. It seems like this could scratch the AR coating, if it is delicate. If the coating is tough, it shouldn't be a problem.
Before I do the experiment and possibly come to tears, does anyone have any relevant experience to share?