The developers of the game have been quite clear on this point. They haven’t hid behind weaselly words or double talk when it comes to the topic of a cheating/rigged AI. They have stated in no uncertain terms that the AI does not turn on secret cheat code to ensure victory. So, you either believe they are lying when they state that they have run hundreds of tests to ensure the AI isn’t developing magical (rigged) luck, or you don’t.
Here is the link where Sirrian shows the results of some of their internal tests:
In this link, Sirrian discusses how these same accusations came up with Puzzle Quest. There were people that were so convinced the AI was rigged. So, the devs released the code for people to see and no cheating was found.
This cheating AI debate has gone on since before I started playing this game. Of course, it never goes anywhere since if someone wants to be convinced the AI is rigged there is nothing the devs can say to convince them otherwise.
For those new to this, here are some more quotes from Sirrian on the topic: