I have a suggestion for this; locking field visibility with a password. This would allow me to make an entry that says "John Doe is the bartender of The Pub" and a locked category that says "He's working for Bigbad and uses false bounties to send heroes to their deaths". This would allow GMs to distribute the file and not have players come across spoilers.
Sure, they could just export it, but that's a player problem.