Disable any development in Finalized branches

When a finished branch gets merged to it's origin (non-reciprocal). It becomes finalized and, depending on selection, archived. Further merging into and from this branch is thereafter no longer possible. Yet, active development is still possible in a finalized branch (even after unarchiving). Wouldn't it make sense to completely lock development in a finalized branch as well? 

I have experienced a scenario where an unsuspecting developer was actively developing in a finalized branch (without knowing it was a finalized branch) and then find out way too late all of his work is for naught.