[agumonkey]

Similarly long ago, a french amazon like site offered (alapage?) a 5e rebate for new customers, one coupon per person, and a person being identified by its delivery (fullname, address) pair. Except that they used string equality as comparison which means every typo combination got you a new account.

Suddenly anything <= 4.99 was open hunt. A month or so later, most item were now 5.01. And possibly uniqueness was now put on credit card number, people can't get more than a handful.

I never could find a figure nor an article in the news but considering how fast this spread around, it was an expensive mistake.