People sell their amazon.com coupons on ebay and other websites. In addition to possible fraud, I wonder how to safely buy an amazon coupon, as it is against the amazon terms.Imagine that I have bought a coupon on ebay, and redeemed it successfully in my account. Is it final? Can't the original owner claim that this is a stolen coupon? And doesn't amazon void a coupon?The reason that I am asking is that a coupon is issued to someone else (not me), and since buying/selling coupons are not allowed, Amazon may (I do not know, I am asking) void my coupon, as I was not the original owner?Is the owner of an amazon coupon is the one who first redeemed it? Or someone can claim?