I don’t know what “better things to do” you’re imagining a clairvoyant would occupy themselves with before having proven themselves beyond the shadow of a doubt to their clients.
How many times more valuable is the advice of a seer who I know for a fact has “the sight” than that of one who I doubt? Say, if I’m the POTUS or something.
To analogise this with the original comment in this thread:
"Last time someone told me they were an actor I simply asked them to audition, for a different part, in front of me" - would be more clearly unacceptable.
If you knew the color of the couch, it costs you nothing to blow my mind. You’re crazy if you think the right and normal thing to do in that scenario is to refuse. If you don’t want to be asked to demonstrate an extraordinary power, then don’t claim it in the first place! If I conversationally mention that I can do six figure arithmetic in my head, I fully expect to be asked “what’s 357453/737901”.
I think we’ve lost track of the fact that the first thing that happens in this conversation is somebody chooses to mention that they possess an extraordinary power. One that can be demonstrated conversationally, even.
You should choose not to engage (in this hypothetical) because you have better things to do with your talent than spend time engaging with people acting unduly negatively towards you.
It's not fraud, it's normal behaviour - in this universe. It's advice I would give to anyone.