This is not quite accurate. The vice president must be eligible to be the President, not to be elected President. The 22nd amendment has some very specific language.
“No person shall be elected to the office of the President more than twice, and no person who has held the office of President, or acted as President, for more than two years of a term to which some other person was elected President shall be elected to the office of the President more than once.”
It prevents someone from being elected President, but does not make the person ineligible to be the President since it only restricts that one method of gaining the office. A person can definitely become President through succession even if they have served their full two terms already…at least by the constitution as written.
Depends on what lesson you think they’re trying to teach. “When you know the right thing to do, don’t let people use rules and obstructions to stop you from doing it.” can be a good lesson.