Interesting couple of videos - if you click through to the first one, you'll get a link to the second part. What are my thoughts, as a Christian?
I would agree that there is manipulation within religion, including Christianity, as Derren Brown says:
Religions tend to encourage either high energy crowd activity or candlelit monotony to invoke a suggestible state amongst the congregation. Many revivalist preachers seem to have a magical touch that brings the power of the Lord into a person.The conclusion that might be drawn from this film is that "religion" is more to do with semi-hypnotic suggestion than the power of God.
In actual fact, the Bible itself (in 1 Corinthians) says that ecstatic religious experiences (if we can generalise from speaking in tongues to the whole range of such experiences) are the least useful component of our makeup as Christians. They may be edifying for the individual believer - and those people who had those "experiences" doubtless thought after they had had them that something significant had happened - but the experiences are at best confusing for other people, and may well lead them to the conclusion that the people having the experiences are out of their mind.
It's significant that ecstatic religious experiences are not the sole province of one religion. For example, glossolalic speaking in tongues isn't only a "Christian" phenomenon; it is found in other religious traditions. (I would suggest that the speaking in tongues referred to in Acts 2 for example was something different - this can be discussed elsewhere.) And there are other forms of religious experience - falling over, trances, visions and so on - that can be found in other religions.
However, there are Christians who are gravely unhappy with the use of manipulation - or indeed any showmanship - in Christian meetings, and frequently they are the ones who are also most wary of deriving anything from nonrational religious experience. I would argue that whilst Christianity ought to engage our emotions, this should not be held in contrast with engaging our mind. Our emotions ought to be engaged because our mind is engaged. If Christianity is true, then our experiences ought not to be "irrational" or "nonrational" but profoundly "rational". And there are many people who don't put down their emotional response to Christianity to something they don't understand, but to something that they do understand, even if they can't fully explain it. There are many other aspects of Christian experience - generosity, hospitality, forgiveness, explaining the Bible, compassion, self-sacrifice and so on. I doubt Brown would argue that his piece invalidates the behaviour of people like Wilberforce, Elizabeth Fry, Martin Luther King and so on.
It was interesting that the minister from whom Derren Brown sought to obtain an endorsement wasn't prepared to simply accept his word about what he had done, but wanted to talk again. In terms of the power of suggestion, it's worth pointing out that when a person stands in front of you with a camera crew saying that they are here for a particular reason (perhaps backed up by a covering letter?), your instinct isn't to assume that they have come to do the opposite. I seem to recall Richard Dawkins being particularly disgusted when a similar trick was played on him by anti-evolutionists, who got him to look silly by asking for evidence for his belief when he wasn't expecting it. There are many more examples of this in the evolution/creation/ID debate, on all sides.
It's also interesting that the minister didn't suggest that this sort of manipulation was an appropriate way of seeking to reach people with the Christian message - he was keen to build genuine relationships with people, so that he could tell them about Christianity. And it's also worth pointing out that the group of people who Brown addressed came to a meeting that they knew was going to be about spirituality - regardless of the fact that they were all atheists or sceptics, they willingly put themselves into an environment where they could reasonably expect their beliefs to be challenged.
So in summary, I would echo the implication of this piece that we need to be wary about the power of suggestion and manipulation - and those that practice it - in the religious arena, as much as any other. However, Brown's little experiment doesn't invalidate the whole of religion, and although he is a sceptic, I don't expect he would say that this experiment alone wraps it up for religion.