The Spectator as Magician (or Mentalist or Mind Reader) plot is one that has always had its share of detractors. Critics will say that it makes your "powers" seem less special and that it turns magic/mentalism into something the just anyone can do. Usually this criticism is made by people in the mentalism community who want their audiences to believe they genuinely have some supernatural abilities. Giving someone else that ability would—in their mind—undermine the fake powers they don't really have that they're desperately trying to convince people they possess. Don't listen to these people. They are deranged and overwhelmed with feelings of inadequacy in their personal life. They don't make good role models.
And their logic is moronic too. Imagine you went to an orchestra concert and at one point the conductor plucked you out of the audience and said, "You're going to play harp on this next number." And you said, "Well, I don't play harp." And he said, "We have the power to allow you to play harp for this one song." The song starts and miraculously your fingers are dancing along the strings and playing in perfect time with the rest of the orchestra. Now the song ends and the audience bursts into applause. What are you thinking at that point? Are you thinking, "What?! How...? What was that?" Or, as those mentalists would suggest, are you thinking, "Huh. Well, I guess playing the harp is easy. Thanx byeeee!"
I don't believe for a second that the Spectator as Magician/Mind Reader plot takes away from the performer in any way. When done correctly, especially in a social setting, it can be a truly unreal and profoundly memorable experience for people.
The problem is this: you hardly ever see anyone perform this plot correctly.
Let me explain...
Let's say you're good with a nail-writer. So you've been doing a trick where you have someone think of any two-digit number and it matches what you wrote down before the start of the trick.
Then you decide that instead of you being the mentalist, you will do this as a Spectator as Mind Reader plot. So instead of saying, "I've predicted the number you're going to think of," you say, "I'm thinking of a number. I wrote it down so I can't change my mind. I want you to try and see if you can read my mind and tell me what number I'm thinking of."
Generally you will find that this gets a stronger reaction. But I think the increase in reaction is due to you shifting the focus off yourself and presenting the trick in a way that is different than what they've seen before.
In reality, I think the trick is only somewhat stronger. You may go from a 5 on the reaction scale, to a 6. But if you want to go to a 9 or 10 you need to give them an experience that feels different in some way.
What I mean is this, if you perform Out of This World for someone, it feels to them like they're dealing out cards randomly, because they are. If you ask them to name what number you're thinking of, it feels like they're guessing, because they are. So you're presenting them with experiences where the only difference is the outcome. So for them, reading your mind or predicting the future feels identical to guessing. They never get the sensation of doing anything unusual because the "mind reading" is only verified in retrospect. You're not really giving them much to believe in here. "When I walked in I wasn't psychic. When I leave I won't be psychic. And when I guessed what number he was thinking of, everything felt normal." You can't really expect the trick to be that much more affecting just because you switched from "I'm reading your mind" to "You're reading mine," if everything else is the same.
Enhancing the Spectator as Magician Plot
Here is how you take Spectator as Magician/Mind Reader to the next level.
For the spectator to feel like maybe they've done something they've never done before, they need to be subjected to a new, or at least uncommon, experience or sensation. They need to do, see, taste, hear, feel or smell something that puts them in a slightly different state of mind. Then their experience of "reading someone's mind" will be associated with a state that is different than the norm. And then, when the outcome is different from the norm, there is a cohesiveness to the experience.
Here's an extreme example, just to make the point: Take someone who has never used drugs before and give them a dose of LSD. Then, right when they're really feeling it, perform Out of This World for them. I promise you, they will truly believe that in their altered state of mind they were granted some power/insight to differentiate between red and black cards. They won't doubt this at all.
Again, that's just a theoretical point. Don't dose people with LSD. But you should do something to put someone in a slightly different state before they take on the role of mind reader or magician. It can be anything: holding their breath, an unusual physical exertion, listening to a particular frequency of tuning fork, tantric breathing, ingesting something unusual, gazing into rippling water, inhaling some mysterious scent, getting a mild static shock. Or put them in a state of low-level fear, or arousal, or bliss. Or go visit them when they're sick and bring some soup and a get-well gift and say, "You know, there's something strange you might be able to do when you're in this condition. Are you up for trying it?" There are countless directions you can take this.
For long-time readers, you'll recognize this is an extension of the ideas of Imps. Imps are particularly useful in Spectator as Magician effects because they justify why now this person is able to do this thing.
Done in this way, you can really capture someone's imagination with the Spectator as Magician/Mind Reader plot. In my experience, if you don't provide an impetus to help explain why they suddenly have this ability, then the experience can ring a little hollow. It may still be a good effect, but the audience won't really entertain the notion that they played a big role in what happened. Instead they will see themselves in the same way they see the magic wand you hold; not as a true source of power, but as a prop you used in the process of the effect.