[zkms]

> The vast majority of the problems with self-checkout machines are caused by the item weight check.

I understand the purpose of the weight check; it's to make sure that an item is in the bagging area iff it has been scanned. I don't get why it needs to be run after each item and can't be run just once -- after all items have been scanned and the payment process begins.

[dTal]

I imagine there's considerable variance in the weight of products, such that any attempted calculation of the final weight of a long list would be unacceptably vague. Also, if there's a single item whose weight is out of tolerance, it needs to be clear which one so that the issue can be resolved.