Now wait, I thought that the reason for it being public WAS so that others would jump on the bandwagon so that the group could get out on the momentum. If it went private, there are guaranteed bagholders amongst the group, buying and selling to themselves.
The only way it would work is if they privately did the play to cause momentum, THEN post about how it's moving so that they can all get out. But wait, there's that pesky stock manipulation issue again...