I personally think that you should not be able to contribute to a section of a profile that you have not updated to the latest approved contribution. I have been burned by this many times and probably others have too especially if you have custom roles for crew members. This will give you the same entry for the same person for the same role.

Example:
John Doe ... Costume Designer with a custom role of Costume Supervisor (still listed under Costume Designer). Then someone does not accept the latest contribution and makes a change or addition and contributes that. You'll play hell keeping John Doe ... Costume Designer with a custom role of Costume Supervisor. It will keep adding John Doe ... Costume Designer (because that's how theirs is still listed) along with keeping John Doe ... Costume Supervisor. Hence you end up with 2. I know it's confusing, but it does happen.