If you've never used the McDonald's app, then you can place an order, but the st...

teddyfrozevelt on Oct 22, 2020 | parent | context | favorite | on: I reverse engineered McDonalds’ internal API

If you've never used the McDonald's app, then you can place an order, but the store doesn't receive it and do anything until you arrive at the store and it detects that you're there. During this period, you can cancel the order. My guess is that's what he's doing.