Have you ever tried to edit your drawing and found that several or all the entities you want to work with are on a locked layer?  PostalCAD has a great pair of tools to help work with locked layers that will make this scenario a snap to deal with.

Enter UA at the command line to Unlock All layers that are locked.  Now make your changes and enter RL to ReLock all the previous layers that were locked.  Be careful here, the Relock tool only works in the current drawing session where Unlock All was used.  You can't close the drawing and then try to recover the locked layer set