1) You are wrong because you said "losing your sources only applies to members of the media". That is wrong, yet you keep stating it.
2) You're logic is all jumbled up. You don't trust him so you ask for his sources. Then you say "I don't need a name, you just could have said someone inside the Spurs organization". If he was lying about the information, could he not just as easily say "my source is inside the Spurs organization" and lie about that? What is it about seeing him type those words out that would make you believe him or trust the "source" any more?
You would have to rely on others on the board not flaming him and calling him out. Which is what I said at the beginning.