The short answer is: we don't, but it's everywhere. Why is this a problem?

Because having carts complicates purchasing. The following instruction was posted at a Facebook event of Budapest Park:

When you click on a [...] ticket and select the quantity, your tickets go to a virtual cart. [...] When time is up, the contents of your shopping cart will automatically be emptied and made available to anyone else who wants to buy a ticket. [...]
So when at ten o'clock in the morning everyone clicks on the Super Early Bird ticket and the website says "SOLD OUT". This means that all tickets are in carts. There is still hope of early bird tickets because not all tickets are paid. When the tickets are not paid, the tickets from the carts will appear as available again.
This is the explanation for the situation where the Super Early Bird ticket type get stamped as "SOLD OUT" in two minutes after release. You will see your tickets at the current available ticket price. If you wait 15 or more minutes you might see the Super Early Bird price appear again.

This is how regular ticketing sites operate. In contrast, in ReverseTicket there is no basket. A ticket is considered sold if it had actually been paid for by the buyer. This solves the above detailed-problem.

Of course, this means: that a few will start the payment process and move to the checkout page. By the time they enter their card number, there will be no ticket left. We can't give tickets to these users, but we'll refund their money right away.

This way, not thousands, but only a few customers will experience inconveniences. This leaves the majority satisfied.

In the case of seat reservation, reservation is only possible after payment. If you want to read more about our seat reservation system read here.