The "Dark Arts-ish levers" are what make this situation interesting. If it were merely a matter of telling the truth, virtually every ethical theory would come out in favor of telling the truth. But having access to such levers is "Here, let me make this choice for you" and that puts you in murky ethical territory.
Some conditional answers from various points of view:
If pulling the lever makes the world rank higher according to your preferences, then pull it.
If both you and they would be better off if you pulled the lever, then pull it.
If your relationship with them properly entails your pulling of the lever, then break off the relationship or pull the lever.
If pulling the levers intersects with duties such that you should pull them, then pull them. If it intersects with duties such that you should not pull them, then don't pull them.
If all of the above criteria come out in the same direction, then you have a pretty definitive answer.
I trust that this answer is not below-average in terms of helpfulness of ethical advice.
Even if it were just a matter of telling the truth, I don't think it would be ethically unambiguous. The more general question is whether the value of increasing some person's net-true-beliefs stat outweighs the corresponding decrease in that person's ability-to-fit-comfortably-in-theist-society stat. In other words I am questioning WHETHER they would be better off, not which conditional I should thereafter follow.
I'm not sure if this is precisely the correct forum for this, but if there is a better place, I don't know what it would be. At any rate...
I'm a student a Catholic university, and there are (as one might surmise) quite a lot of Catholics here, along with assorted other theists (yes, even some in the biology faculty). For this reason, I find myself acquiring more and more devoutly Catholic friends, and some of them I have grown quite close to. But the God issue keeps coming up for one reason or another, which is a source of tension. And yet as I grow closer to these people, it becomes clearer and clearer that each theist has a certain personal sequence of Dark Arts-ish levers in eir head, the flipping (or un-flipping) of which would snap em out of faith.
So the question is this: in what situations (if any) is it ethical to push such buttons? We often say, here, that that which can be destroyed by the truth should be, but these are people who have built their lives around faith, people for whom the Church is their social support group. If it were possible to disillusion the whole world all at once, that'd be one thing - but in this case my options are limited to changing the minds of only the specific individuals I have spent time getting to know, and the direct result would be their alienation from the entire community in which they've been raised.
And yet it is the truth.
I'm conflicted. LessWrong, what is your opinion?