I believe ( I have never owned a casino and never managed a casino ) that all casinos have employees who are people who are experienced in coding, so when the casino pays a gambling provider, the casino employees who are responsible for the coding must be able to audit the games that are added to the casino, this ensures that the casinos do not make agreements with game provider companies that manipulate the games, because let's imagine the following case, a person builds an online casino, then makes an agreement with some gambling provider company, then how can that person be assured that the gambling provider is not causing
Anyone in particular exploit some glitches in some games? something like the gambling provider agreeing with someone for that person to go play at the casino where he recently made an agreement with the company, that person would know all the flaws in the game because the provider told him, so that person would always be making money and would share winnings from the gaming provider, because these kinds of things would be possible to happen, so casinos need to have employees capable of auditing the games provided by the gambling providers
casinos would not be naïve to simply take the word of gambling provider companies, at least I say that because if I were a casino owner I would not believe and would not trust 100% in gambling providers, I would have hired capable employees as well to audit everything that was added to the casino that came from other companies, this is the norm of operation of many companies. Of course, game providers also want to have a good reputation in the market and that's why they strive not to get involved in scandals and provide reliable things.
The gambling had many team including the coding team which play huge role in the website.Mostly gambling sites keep their developer with them,because they know the extract movement of the gambling site.The gambling company will creat some contract with the coding developer and it exist till the website was survived in the market.Because the developer can bet on the point which give them maximum win,So the friends and relatives of the developers also in the monitor list of the owners.The gambling owner should build the trust among the gamblers,So they get more gamblers to their sites.