With many games of luck and/or strategy, some people find it difficult to believe that their software opponent doesn't 'cheat'. In case you're one of them, we'd like to address the matter with three different approaches:

The Rational Approach
Frankly, we can't understand why anyone would ever write a game that cheats unless it somehow channelled money to them. We wouldn't support that, but we could understand it. In the case of Electrum Dominoes, the only way any money will come to us is if people buy the full version. But they're less likely to do that if they think it cheats. So it's in our interests to present a game that can be seen to play well and honestly.

The Practical Approach
You can demonstrate for yourself that it doesn't cheat. If you have the full version, you can look at Nestor's hand and the boneyard and see that draws are random and that bones don't mysteriously appear or disappear. You'll also be able to see cases where Nestor could score if he could see your hand, but doesn't -- because he can't. Even with the free version, you can undo plays that caused Nestor to draw and observe that he draws different numbers of bones or plays a different bone (if at least two playable bones are in the boneyard) when you repeat the same play. You can also start new games repeatedly and observe the random distribution of bones in your hand over time.

The Technical Approach
If you were going to write a game program that cheats, you'd have to understand how to make one side win and get away with it. With a game like Dominoes, it would be at least as difficult to write a game that cheats well as it would be to write a game that plays well. If you didn't do it well, everyone would know you did it. So why would anyone do it at all?