ok, my items are one of a kind:
https://www.cvtreasures.com
I don't sell manufactured retail products, but one of a kind very rare collectibles. So when someone hits the Buy Now or Add to Cart, that's it, the item is sold out. ANd it works ok 95% of the time. But, there are buyers who will click the button and because they are not immediately taken to their shopping cart might click the buttons multiple times. Now when the item is ordered Once and the quality is then Zero, then any additional clicks to the Buy Now or Add to Cart should product an error message, i.e. Sold Out or No Longer Available. But it doesn’t. The cart registers those simultaneous clicks and I have seen where the quantity will say -1 or -2. Actually go into the negative. It seems to happen only if the buttons are clicks fast, not as it should such as after the order is fully processed, then they WILL get an error if they try to order.
This scenario results in havoc to the shopping cart as it will show 2,3 or 4 of the SAME item, even though ONLY ONE was available. It just happened the other day and instead for $1500 in the shopping cart the buyer’s cart showed $6000 and almost scared him away completely and would have resulted in a lost sale if I were not on the phone with him when it happened.