What a shitty store. I use self-checkout 99% of the time, but you should have a choice and the store should always accommodate at least one of each. Scanning an entire cart full of groceries is painful for you, the employee correcting the machine, and the people behind you.
Obviously it’s different with every store management/owner, but any decent store would never ban you or try to press charges for missing one item, especially if it’s obviously a mistake.
Also, leaving a cart in the parking lot does not impact the store at all, you’re simply punishing that kid for no reason. A simple call, email, review, or social media comment is much more impactful because it actually reaches the decision-makers…