Is there a way to prevent editing of metadata? If not, this would be a great feature to have, similar to security settings on PDF files.
I would want to retain all my metadata and prevent it from being edited or stripped, while still being able to view it.
You can lock a file in Bridge (right mouse click menu in Bridge content panel) to prevent writing to it but like Paul stated, this only helps you to prevent changing accidentally metadata. Whenever a file is out everyone can unlock this file or you only have to open it in PS, use select all, copy, create new file and use paste to end up with an exact copy of the image data yet all metadata has been stripped…
I seem to recall that in the early days was a company in France that offered some digital copyright in the file itself that would secure the rights abuse but that was long ago and proofed not to be safe at all.
Password-protecting metadata is something to consider, although it is highly dependent on the OS. Photographers and digital artists would use this to authenticate ownership, especially if the work is natively digital and ia a part of an autographed edition.