Basically, all of us have Signature Skill for all skills.
Halasik:
The solution might be for the judge to take all of the written down questions and choose one at random face down to hand to all of the contestants, so that the judge doesn't know which question was chosen and thus can't be thinking of the solution. However, saying that would imply that everyone is cheating, which might not be a great idea.
Oh, please do imply and reveal that if you have a good way to prove it. The advantage of doing it Diata's way is that she isn't breaking any rules, she's just a skilled observer.
Problem is, to make that suggestion you'll need evidence that Zakhar's team is cheating, and at that point it's not needed.