So, unrelated to the current vote, but I had an epiphany. Unless Mao is somehow radically different from canon Mao (like being Exalted, which I seriously doubt because it seems probable to me that Geass is incompatible with an Exaltation) then if he ever tries to use his Geass on Lelouch as his strategy he'll be fucked over for it.
Why? Assumption of Mu. Mao's Geass reads minds. It reveals information about those in range. It essentially asks "what is this person thinking" and gives Mao the information. So, what will the answer be for Lelouch? Something he's not thinking. Could be anything really, because the 'question being asked' so to speak is completely vague - his power doesn't ask "what move is Lelouch thinking of making" when they're playing chess, it's just asks what all of Lelouch's current surface thoughts are and gives Mao the information. And there are two ways this could really end up...
1. His Geass gives him a stream of thoughts that aren't what Lelouch is thinking at all, and are just kind of random and bizarre.
*Mao gets in range*
I am not thinking about pancakes.
M: "I... what?"
I am not thinking that Britannia is awesome.
L: "Hmmm? Knight to H3."
I am not thinking that Mao would look fantastic in a dress.
M: "WHAT!? OF COURSE I'D LOOK FANTASTIC IN A DRESS! C.C. dressed me in them all the time! Er... I mean..." *blushes*
L: "...ok? Checkmate."
2. His power is constantly active, and feeds him the information live. If someone got out of his range mid-thought the info would stop there. We know that thinking of multiple solutions at once doesn't really work - he gets all of your solutions that you thought of and the one you decided on as the information. However, we know there's a limit to how many thoughts he can handle at once because being in a crowded place affects him badly. This may merely be psychological, or his brain literally has difficulty processing the information.
It may be the case that here Assumption of Mu treats his question as being asked repeatedly for every possible moment of time down to the planck second. In this case he gets an answer every planck second, effectively bombarding him with complete or partial things that Lelouch is not thinking at the time the question is being asked. If it gives the complete answer, then he's effectively being bombarded with what amounts to infinite information, at which point he'd probably either lose it or his brain would simply force him into a coma from information overload. Even if he didn't he still would have to parse through the infinite information to figure out what Lelouch is actually thinking, which would be difficult as hell. If it's only partial, it would probably give him nothing but an infinite amount of gibberish, meaning he'd probably hear annoying static white noise in his head when around Lelouch.