I had my IWC on whilst driving my motorcycle.
when I wanted to park it next to my house, I came to close to the wall with my wrist and my watch scratched the wall..
Surprisingly the glas of the watch wasn't scratched at all, of course the SS case of the watch did.
I had it serviced at IWC (SCHAFFHAUSEN) and the watchcase came back as new.
so in short I would not worry about it.
cheers