"I believe Darren uses the common belief that we're all unconsciously influenced by hidden messages to the advantage of his gig."

In other words, you are saying that suspense is a tension and a resolution, the latter is always the discovery of something we already know, and in this case something planted there. Very much like that which you critique, who claimed that Darren planted the word ONE without the participant realizing it -- this likeness doesn't make it wrong btw. Darren Brown would then be -- not a genuine manipulator -- but a manipulator of manipulation, manipulating the ways that manipulation occurs. Incidentally, it may be compared to reality porn, porn always being about manipulation, or perhaps anything having to do with women. I can only watch Bangbus, for example, because only that seems credible or not fake, but of course, even that is still planted.

What you are doing is halting a regime of study where this act can be reflected on for evidence on a subconscious event (of cause and effect) and proposing that the manipulation extends to the very planting of that regime. In general, we are always within a regime of manipulation, blindly finding things that have already been planted, but not by a person or a human agency. (So we are not conspiracy theorists!) Whatever labor we propose (even what you propose) is always a digging up of something that is already there -- the key is to think beyond the Darren Brown as a person or a mastermind, but perhaps of the media itself.