It's actually an interesting problem to solve. You would think that a particular item weighs the same no matter which store you scan it in, but in reality item weight can vary. Sometimes it is due to the manufacturer changing the packaging or adding a free sample of some other product to the item, but more interesting it could be the region. One chain I worked in had issues w/self-checkout on paper items such as toilet paper, paper towels, etc. The items were all weighed in the home office in Massachusetts and input into the master item file. This worked fine in most of the stores. The stores in Florida however always had issues because, due to the humidity in the air, the paper would absorb some of that and be just heavier enough to trip the scales. Eventually it was fixed by adding a larger weight variance allowance to the southern stores' POS registers.

> I have given up on bagging as I check out. It goes crazy every time I open a bag and set it in the bagging area. So now I just pile up my groceries and bag them when I'm done, which wastes everyone's time.

This. Trying to do the following

a) Open one of the cellophane bags that are stuck closely together

b) Put the product I just scanned in it

c) Take my hand away so it reads the weight correctly

...are way too difficult for me to do without the machine locking up and saying "okay, assistance required, let's hold you up until the overworked 1 person for 12 checkout machines gets here". So I do the same thing you do, just throw them in the checkout area and bag later.

It wastes everyone's time, but sometimes allows me to bag more efficiently and use fewer plastic bags.

We don't have plastic bags anymore in Seattle. The act of opening a paper bag and setting it on the scale (or simply opening a reusable bag that I'd already set on the scale) is enough to make me "require assistance" 99% of the time.

The ones in supermarkets in Australia started off with a lot of weight related issues. Seems to work fine now, not sure if they have gotten smarter or just less picky with weights.

At the mall where I live, Woolworths insists on bag weighing but Coles actually has it turned off!

This is awesome, as it's incredibly time-saving. At Woolworths I generally have to look like a doofus holding my next item to scan in front of the scanner for at least 2 seconds while the machine is frozen as it slowly weight-checks the item I just bagged...

At Coles the bottleneck is the speed at which I can bag things. Usually I just cram as many things into one bag as possible (I always repack later) and checking out takes under a minute.

NB: The Coles where I live is toward the back of the mall and reasonably far away from the center's exits. I think this has had an impact on the number of items that go walkies, which is why they were able to disable it. (The Woolworths on the other hand is practically outside - leaving there is like going through airport security, they physically rummage through your bags!)