> > You don't need scales in the cart.  As the item gets added 
> it talks to 
> > the server (needs to get the price anyway) and gets the weight.
> >
> > You weigh the entire cart at checkout.
> 
> The problem the scale was tryign to solve was 100 pounds of 
> cheap groceries with working RF tags, and burried deep in the 
> middle, an expensive flash memory stick with a broken tag.  
> The weight of the memory stick is far less than the tolerance 
> on the food packaging. 


That's a valid case, and yes, in that scenario you get a free memory stick,
or more likely a free broken memory stick.

Solutions to this already exist.  You can strengthen the packaging to
prevent damage to the tag, place the tag inside the product, or make the
package heavier.

The eventual solution will be the same as it is now; small, expensive,
fragile or otherwise special products are simply handled differently.  In
Australia, you can't throw a carton of cigarettes in your cart and have them
crushed simply because they are only available behind the counter.  You can
only buy them after you've purchased everything else.  Other items are in
locked cases.  Special areas exist for certain products (store within a
store) and are paid for there.

Holes exist in all systems, but a single edge case failing isn't enough
reason to abandon it.  Bar codes are easily damaged, scribbling on them with
lead pencil causes the scan to fail (carbon + IR light), people stick fake
ones over the top, and aluminium cans are hard to scan.  The advantages
still outweigh the hassles.

Tony

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