Lock Entire Layer

I would like the ability to lock an entire layer. maybe password or pin protected from other users.

I have project managers that use their own layer to do takeoffs etc.. I want them to have full takeoff access to the project but only be able to view and copy my original takeoffs to their own layer and not be able to modify my original layer.

Once the project is under contract I want to lock the original layer if that makes sense.

Are there any work arounds that already exist?