Well, it depends on what it is they are doing.
Just because someone is a professor, doesn't mean that whatever he's researching is always correct.
He's just a human being, and thus he can be wrong. Being a professor doesn't make him right.
So you're saying you know how to time travel, but only tell it people you consider "worthy".
That's not very original and if you'd really don't care if people believed you, you wouldn't even say such a suggestive remark. But since you said it you just want some people to hang on your every word, because they think you can time travel and you might tell them if they are just behaving worthy enough.
This way you conveniently diminish the amount of people scrutinizing you for not backing your claim.
Sorry, but I'm not falling for such methods, but I guess saw that coming.
But since you started, let me tell you a secret myself:
I know about teleport, but I won't share the details.
And I'm not lying! I know how to teleport, it's just that I think not everybody should have this ability, because then someone could just kill another person and teleport away to get an alibi.