http://www.reddit.com/r/Bitcoin/comments/2po40d/since_my_house_is_being_searched_right_now_small/
Um... only because you believe that nobody will do that doesnt mean that youre right. In fact purse.io is doing it since a longer time already and they collected, i believe, 400K USD in seed funds. Check out the support thread on bitcointalk about it. You can get 50% discounts. I did.
Unfortunately they become more and more restrictive. Didnt allow buying of amazon coupons anymore, then stopped external products in wishlists and now a whole country is blocked. I wonder if they fix their things.
They stay in business since a longer time now. So it seems to me the problems you see arent happening often. At least i would await users writing about that in the support thread.
And as far as i know purse.io is aggressively advertising the possibility to exchange ones amazon coupons into bitcoins. Im not sure where people get all these coupons from but there are a lot of people who have many of them.