Unless there is some "provably fair" mechanism built into a game, then casinos absolutely can engineer the backend to do whatever they need. They can monitor and build algorithms that can take advantage of every different aspect of your game, even tailoring the response back to the balance that you have in your account - they might give you 9 out of 10 parts needed to complete a side game, but drain your wallet without letting you unlock the extra bit, knowing that most people would top up their account to keep playing and get that last 1 in unlock the side game. Unless you have full visibility of the code or a reliable third party can vet it, you have zero knowledge on what they are really doing behind the scenes. That being said, casinos don't need to cheat - they are full up front that you will lose all your money over time and people still play.