Pull up http://cprince.devel.webdevel.redhat.com/cgi-bin/store and place one of the Professional Server boxes in the cart. Will get taken to the cart and there will be a T-shirt listed in the Additional Items section. Click buy on this, thus adding it to the cart. Now the list of suggested items changes, and the new list will include "Red Hat Professional Server" It's already in the cart, we should not be suggesting that the user purchase this product.
Fixed, items in the cart are now prevented from appearing in the crosssell/upsell list.
Looks like we know have debugging statements appearing just below the Cancel Order button. Looks like the part numbers for the cross-sell or something like that. Other than that, the only issue that I see is if the customer has all of the cross-sell items in their cart, then we get "You might also like" and nothing. Looks a little odd.
That was the cross_sell list, so I could make sure the items were actually getting removed, I just hadn't saved the file after deleting it yet, it's gone now.
I've modified the cart to not display the 'You might also like' text if no cross_sell items could be found.
This appears to be cleared up on webdevel, so I'm closing out the issue.