On Sat, 3 Mar 2018 10:14:27 -0000
"NY" wrote:

Well I've learned something.

That people on the internet spout ********.

Ever since the system was introduced,
I've thought that the system knew the weight of every item and
checked that the scales increased by that weight after it had been
scanned and was placed in the bagging area.

That is indeed how they work, at least in the supermarkets I frequent.
When the peanut butter I used to buy switched from glass to plastic
jars the system still expected the heavier item, and raised an error
every time I scanned one for months after the change.