[rab] With the "Whoops!" button, could one undo a winning move? More pertinantly, could one test several options until finding the winning move, if unknown?
[rab] Yes and no, eh? There's cards close to the chest. I'm too timid to go test it ;) And regarding the second, in theory, with patience, one could knock off the likes of Mystery Crescent single-handedly.
Yes, but you could do the same thing, albeit more publicly, without the Whoops feature. If anyone ever suspects foul play I can always look at the logs.