If Micay says, "The code does X," anyone who can read it can review it and say, "No it doesn't. It does Y." It's right there. You don't have to trust him. He's shown it to you.

It doesn't matter what the code actually is, or that you can see it, you still have to trust people because there is simply too much of it, even if you happen to be a coder, which 99% of people should not be required to be. This is a FUCKING MORONIC thing to have to spell out, but I guess here we are.