Bill:

Randi's expertise is in debunking people who run sleight-of-hand or other rigged scams. He would not be a neutral observer or a Fair Witness, to use Heinlein's term, in an experiment calling on psychic abilities. Not that such an observer is not possible, by any means. But in testing the "mind" itself, non-interference is a critical element of a fair test. Otherwise it is like tying an anchor to Orville's ankle to challenge his ability to fly.