LJ has a few problems lately. You may have heard about LJ deleting journals. And outages. As a side effect I've noticed when I lock a post it doesn't stay locked. Last month I had to lock a post literally three times. It finally appears to have stayed locked. I'd been somewhat distracted and LJ had yet more problems and it appears to have happened with a recent post. I apologize to those who read the post and thought it was public. It was not meant to be.
I used to work in computer security so I tend to think no lock is secure and even in my locked posts I don't use RL names unless the person has given me permission or it's a matter of public record. Even so it's annoying because I lock posts so people know what I'm writing is meant to be private.