> >        Chances are there will be a database that would should
> that your particular
> >item had already been paid for, at least that's how I'd do it.
>
> Hmm. That could be problematic. That database would get big real fast.

        True, but database technology has gotten so good I don't see it as being
much of a problem.

> There's also the problem that I might have bought it at a
> different store, or a different retailer.

        Not a problem, the store will no the item scanned was never available at
that location, therefore it won't charge you.

> >Another option is to flip a bit in the tag to signify the item
> as "sold". TTYL
>
> Boy that would be rife for thieves!
> Bit flipper boxes on ebay..

        Smart card technology has come a long way, I don't think it would be much
of a problem, plus there is always the human "big brother" element.
Remember, people are going to shoplift no matter what. TTYL

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.