If you were to say tomorrow "I've been lying about the whole AI programmer thing; I actually live in my parents' basement and have never done anything worthwhile in any non-rationality field in my entire life," then would I have to revise my opinion that you're a very good rationality teacher? Would I have to deny having learned really valuable things from you?

But the fact that reality doesn't disentangle this way, is in a sense the whole point - it's not a coincidence that things are the way they are.

If we get far enough to have external real-world standards like those you're describing, then yes we can toss the "secret identity" thing out the window, so long as we don't have the problem of most good students wanting only to become rationality instructors themselves as opposed to going into other careers (but a teacher who raised their students this way would suffer on the 'accomplished students' metric, etc.). But on the other hand I still suspect that the instructors with secret identities would be revealed to do better.