It would be nice to have some sort of default permissions for Linked repositories in Bamboo, similar to what Fisheye & Crucible have, where you can manage default access permissions for all repositories:

This way administrators can decide which users, groups and roles should have default access to all Linked repositories created in Bamboo. For example, if you do not want to allow all logged-in users to have access across all Linked repositories, you could easily uncheck the Grant read access to all logged in users option, as opposed to the current behavior, where admins must immediately correct permissions after creating Linked repositories and must also review the creation of all Linked repositories to ensure the correct permissions have been set by other admins. There's no way to manage all this from one place.