Like the subverter in a paranoid debate? I think that would actually be really useful, or at least a lot of fun (which has a use in and of itself.)

I would stipulate that it NOT be just one person, though. There ought to multiple people, trading off to diffuse attention, or whoever is designated could easily become a strawman effigy to be mocked and denounced.

The story in my head goes: Every once in a while, an ace of spades (if we can get it custom, red or gold on black would be an epic color scheme), will be discretely slipped to a randomly selected acolyte or two before the meeting has begun. These people have license to be as contrary and anti-consensus as they can get away with without being found out. It will be given away at the end of the meeting, unless they'd like the actions and statements they made that day to stand as-is...