Um... I had a sensei at the early stages of my Aikido who said he wouldn't give 5th kyu to someone if he didn't think he could "take" a shodan in most other martial arts.
Do I believe I could "take" a shodan in most other martial arts? - Don't really want to find out. Did he believe that? I'm not sure
If he believed it, he was almost certainly kidding himself. That's an attitude of willful ignorance and delusion.