Searle thinks that consciousness does cause behavior. In the scary story, the normal cause of behavior is supplanted, causing the outward appearance of normality. Thus, it's not that consciousness doesn't affect things, but just that its effects can be mimicked.
Nisan's criticism is devastating, and has the advantage of not requiring technological marvels to assess. I do like the elegance of your simple solution, though.
To whom it may concern:
This thread is for the discussion of Less Wrong topics that have not appeared in recent posts. If a discussion gets unwieldy, celebrate by turning it into a top-level post.
(After the critical success of part II, and the strong box office sales of part III in spite of mixed reviews, will part IV finally see the June Open Thread jump the shark?)