Currently we do not stop users from being able to exceed the funding limit. We are looking at implementing an option to inhibit users from being able to exceed the amount. As of now, the project will show how much the users have gone over the allocated amount.
Although users can exceed the limit, they are not able to use a funding code past its expiry date. As such, we recommend putting an expiry date in the funding code, and investigating the status once the expiry date has past.