So, what would you do in this situation?
You log onto a popular resort website to look at ticket specials. They have discounts for multi-day passes -- 2, 3, 4,5,6,7....I think you get the picture. Multi day purchases have to be made 7 days in advance, and are non-refundable within 7 days of use.
So...scrolling down you notice that...instead of a 15% discount, the 6 day pass has -- a 100% discount!!! Surely this must be an error, right? Just for kicks, you add one (or maybe four) to your cart, and it still shows up as $0.00.
You can press the button, and see what happens. Either it will get rejected by the site, or someone will notice the error and catch it, or you'll get free tickets. Or...maybe the last step finally charges you the right amount through another software "feature".
Do you do it?