Keeping track of transactions on guest carts

This message was sent from: Tips and Tricks
http://forums.oscommerce.com/viewtopic.php?p=225839#225839
----------------------------------------------------------------

Howdy, all...

I've got a website that contains unique single-quantity items.  As such, when one customer puts an item into his or her shopping cart, its quantity should be set to zero.  That way, nobody else can add it to their cart and create a situation where two customers check out the same item when we only have one in stock.  

The solution to this would presumably be to set the item's quantity to zero when a customer adds it to his shopping cart, and then have a timer keep track of inactive shopping carts, returning any unpurchased items to the inventory after a set time of inactivity (i.e., deadbeat customers closing their browsers midsession).  I've got someone working on this, but he says that there's no way to keep track of individual transactions on shopping carts associated with a Guest user.  His direct quote is, "The OSCommerce design does not permit keeping a check on the basket contents of a person when they are not logged in. (logged in as a guest)"  Is this true?  I find it unlikely that there's no way at all to keep track of which customer is which, especially when that information is presumably used for checkout.

Anyway, any suggestions?