Creating based on customer's request:

We only greenlight users into repositories if they're working on the project - otherwise, they should have no visibility to the repo. We achieve this by setting all projects to default to no access.

However, some folks will not follow directions and will change this setting when creating repositories. We would like to disable this setting so that it can never be set to anything other than No Access. Is this possible? As we occasionally give access to external clients, this is fairly critical to us to ensure that clients never have access to other clients' code.