When you add a folder or a document to a parent folder, access permissions automatically apply to the new child members of the folder.
If you subsequently modify the permissions of the parent, the children keep their original permissions and vice-versa. For example, you can modify the permissions on a package without affecting the permissions of its parent model.
If you want to restore the permissions of a parent over its child members, you have to use the Copy Permissions to All Children tool in the Permissions tab of the following property sheets: