Was it FL that allowed for price negotiation via values placed in HTML forms? This was decades ago. Websites would send the $-values of products via html elements that the frontend designer wasn't expecting to be modified before the order was sent back from the client. The order system read the values back in and calculated the amount owed using these manipulated values. The naive, fun days of the adolescent web.
ISTR a slashdot era story about that. Someone found a computer company order form that accepted modified prices; sent them a note about it, and got blown off, rudely.
So they ordered the entire shop for $0.01 per item or something.
Then they posted the story. I think partially hoping the publicity would keep them from being prosecutable; they stated they had no desire to defraud but wanted to help and couldn't see another way.
I have a dimmer memory of there being a similar problem with a popular PHP "shopping cart" script that was widely deployed. The thread that popped it said "try this on your site" and the replies were 95% "oh shit" and 5% "you bastards ruined my trick!"
