I think it's a fantastic idea as well!
I am also wondering if it would only apply to new bags purchased at boutiques or for any MJ bag you own you could purchase the warranty separately?
that's why I was thinking that it might be a better idea to charge a nominal fee for repairs as they're needed (beyond the initial warranty period, which should be automatic for a certain period of time) -- what if you buy a second hand bag and something goes wrong, but the original owner didn't buy the extended warranty?? if they charged on an "as-needed" basis, you could still have it repaired for a nominal fee