Einstein discovered to his horror that Hilbert had taken what he had learned from Einstein's lectures and was racing to come up with the correct equations first.
Since the Copernican theory of planetary motion is inconsistent with the Ptolemaic account, Galileo's observations of Jupiter's satellites proved the truth of the Copernican theory.
Since they require the programmer to do all the detecting of problems by hand, it's easy to manipulate numbers incorrectly in a way that's exploitable.
Sometimes parents regard their children as extensions of themselves and think it only right and natural that they determine what their children do with their lives.