A scam most-likely won't happen at long-standing casino, which already has good reputation. If you want to minimize risk - don't try freshly opened ones as there are decent amount of proven websites that offer options to satisfy anyone's needs.
That's true that the old ones won't allow something slip their reputations that has been built through the entire time that they have been operating.
Hardship and hard work made them to the top and gained their reputation along their way, it's not easy for a casino to gain reputation and it's a business. They won't allow something to ruin their reputation because it will ruin their business.
Newly created casino's are likely to scam so if there's someone who loves to try them out, beware and cautious.