People are very rules based, they create certain rules for themselves to be able to cope with life and then force you into those rules as well. It doesn't matter how professional done or useful something is, if it isn't sanctioned and someone finds out about it, expect it to be gone.
They kept his suggestion. After 8 years, they added his "patch" to the new sign.
Except that Caltrans knew about this and decided to leave it up. Thus invalidating your entire worldview!
The story says he came clean about it in the news shortly after he put it up, yet it remained there.