If that was the answer i would expect that at least after I had visited the page with the checkout control on, then if it created a new one it would then drop a new cookie, and so the second time adding something to the cart would be successful. But it does this every time. I can see the item appear in the database, then refresh the cart, and it's gone again.
Also, if it couldn't find the cartID, how would it delete the cartitem row :-) ....
Also, if it couldn't find the cartID, how would it delete the cartitem row :-) ....