If they notice, they'll probably complain. Nintendo is fairly hardline on this kind of thing, afaict. An academic conference in my area used to host an annual "Mario AI championship", where competitors submitted either Mario-playing AI controllers, or systems to procedurally generate Mario-like levels [1]. After a few years someone at Nintendo found out, and demanded that we: 1) stop using the name "Mario", and 2) st…
Although the SC AI guys are still stuck with BW, not SC2 :'(
I have seen one SC2 bot, based on the rather impressive feat of intercepting raw DirectX calls and reconstructing game state from them: http://graphics.stanford.edu/~mdfisher/GameAIs.html