Remove the ability to add a discount code in the cart

We are finding that when a customer has a discount code that we have defined as being available to a specific Group, and they try to add it to their cart, prior to being logged in or having created an account, the system pretends to process it but never adds it and does not provide an error or reason. I know we can add the "not logged in" as a group to the discount code rules so this doesn't happen but since the system doesn't show an error when they do this, the customer thinks the code is broken.

It would be nice to have the ability to choose whether the discount code and gift card fields do or do not show up until they are in the checkout process?