It is weird how some people have this mystical idea of an insider like they either know EVERYTHING or they know nothing ...
Like most insiders are actually someone that knows as much as you or me and happen to know ONE PERSON who like did a translation for ONE GAME and that person got a little too excited. Or it is a person from one dev team that because of the companie's secrecy knows shit about the rest of the company.
And that is ignoring when people think that everyone leaked WILL be released. Like there are no interal delays or cancelations or project changes. If someone leaked a brand new ip from rare for the gamecube and suddenly star fox adventures appeared they would say the person was lying.