I agree that having the panel decided in advance would be better, but I don't think that discredits the overall challenge, or the goal. It doesn't say you have

I agree that having the panel decided in advance would be better, but I don't think that discredits the overall challenge, or the goal. It doesn't say you have to decide the panel make up after you start, so there is no reason to assume you couldn't negotiate that up front. If the author is making unreasonable demands during that negotiation, you've lost at worst an hour or two of time emailing back and forth, and you can write your own article fully discrediting this challenge. I guess my point is that potential for unreasonable demands, doesn't make this challenge any less (or more) valid. Regardless, I appreciate your perspective on this, and your willingness to engage in a discussion of it.