It might be possible that they have designed the software to payout 50% of all player deposit with in 24 hours and no matter how you play you can not suck out more than the previously fixed amount.
Some payouts are checked/done by hand which takes time. Of course, some may just claim to check, some may check when it's not the case.
But just think that they did the same in 2017 and then the players got more $ when the casino delayed the withdrawal. So no, you better go with the mindset that 1 Bitcoin = 1 Bitcoin. It could help you stay same in years like 2018
but I am more interested in the technical type of cheating behind the curtain.
If you want technical, we're back to provably fair. As others said, with provably fair your bets can be checked.
In theory the casinos could get 3rd party audit now and then for extra trust.
In practice, and this is what interests you, I guess that a casino could "cheat" and not all the bets would be provably fair. But I think that sooner or later such practice would be caught and then that casino is doomed and the owners will face lawsuits. So imho it's not worth it, especially for big established casinos. I mean, why would somebody risk to ruin a well working business for some extra bucks?