What about a View Only mode or a lock-out feature where the only tools able to be used are the Show and Inspect tools. This would be great for firmware guys to jump in and verify the port connections without running the risk of accidentally making a change and saving. Or for a technician to pop in when assembling a prototype or setting up a pick and place machine.
It wouldn't even need to be a modification to the existing editor but a seperate viewer program that is only capable of viewing the schematic and board in a stripped down and clean interface.