I expected others to say that. Can't Google just allow anyone to play against it online after these 5 matches with Sedol conclude?
If they would release the (trained) AI to everybody, that would prove that the training phase is general enough to beat any player, not just one.
Google doesn't have to pay for the CPU time. Ke Jie can find sponsors if he pretends he can beat AlphaGo.
(Edit: clarify)
edit: table showing gains as CPUs are added - https://i.imgur.com/xxdWUtV.png
[0] https://cloud.google.com/products/calculator/#id=f63f1fe0-56...