Let's assume they are.
But what if they bet on their own game many many times, wouldn't they increase their profit by doing so?
If they create the highest betting volume, they have a higher stake in the whole game.
Do I miss something?
I don't think that there is any possibility of cheating when game is provably fair..
Here it is well described:
https://satoshidice.com/provably-fair/
The site operator could still cheat the investors. By knowing the server seeds they could predict any roll outcome and drain the bankroll. Checkout our site https://rolldice.io, we developed a solution specifically to this problem, also checkout our thread at https://bitcointalksearch.org/topic/rolldiceio-the-first-provably-fair-for-investors-and-players-bitcoin-dice-game-920704
Correct me if I'm wrong but your site isn't provably fair and I showed you this.. lol
Check our Fair page, you will find a video which shows you how to do a manual verification. Our site is 100% provably fair, please do not spread false informations.