Maybe someone later has some legitimate edit they want to make to the file, which fails because it's immutable, which is in turn very hard to figure out. (E.g., I didn't know that there exists an "immutable" attribute.)
Put a comment in the file with the exact commands to turn on and off immutability. This is just good practice for most things. Having a maintenance text file with all the system stuff is a secondary good practice along with the comment.
