submit does not add to cart if node edited after failed hook_add_to_cart()

I have implemented ubercart's hook_add_to_cart() to call for a check on my checkout node before the product is added to the cart. My use case is that I don't want to allow a product to be added to cart if the node checkout associated node doesn't meet certain criteria found on the product. By returning $result[] 'success' => FALSE, I can stop the node from being added to the cart and post a message stating "Your node submission does not meet X criteria". The problem now, is that if a user goes back to the node checkout node, edits it, and corrects the problem, saving the node, no longer adds the product to the cart.

I'd like to take a stab at this, but not sure where to begin.