Very small or new casinos can be fixing games which is the reason why people stick to the well known ones that were reviewed by many people and have good reputation. Those will never scam you because the reputation is worth a lot of money. Much more than they would be able to steal from you. Be aware of exit scams though.
I think the new casino's usually people not believe because once we lost our money there is no way to get back our lost. and yes some people will create a site to cheat people that's why always prefer old reputed sites. If you face any problem just report in this forum they will solve asap and i don't think all online games are fixed.