You REALLY got my attention on this one. I've never heard your 'claim' as have ever occuring. Worn carpet and stains are part of 'normal wear and tear', and items that require 'regular maintenance'.
If your policy covers it: 1) How's it written into the policy? (As a rider?) 2) What's your insurance company? (Because I'd like to see their rates.) If they cover damage due to stains, I have to wonder if they also cover things like spoiled food, shrinking clothes, and burned out lightbulbs.
Really, I'd like to hear back from you on my ?'s. Like I said, you've got my attention.