So then wouldn't they ask personal stuff about "jacob" that the psychic couldn't answer? that would really screw the psychic up...
The psychic is always in complete control of the situation. People don't bother asking questions, they are hungry for what the psychic can tell them. You have to understand the people who go to psychics go there to be "psychically read". They are not there to challenge the psychic
They are not testing to see if the psychic is real, rather, they assume it from the start and want to hear what they have to say.
Therefore, they psychic can take advantage of their non-cynicism and easily convince them.