It would be useful if there was a security permission or system setting which controlled whether users could add code table entries by entering them into data forms so that we could require that users who needed to create new code table entries had to go and directly edit the code table.  This would avoid the accidental creation of new code table entries by mistyping a code or typing a code into the wrong field.

Most of our users don't have the rights to create code table entries anyway, but even our administrators can make a mistake.