I received an email from someone who thought that the Indian casinos in Oklahoma cheat their customers by rigging their slot machines to pay back especially low percentages. I didn't think that was true and below you can read his question and my answer.
Question - You should go to a Indian casino in Oklahoma and Play for 2 hours and take 10 other people. You would see for yourself. Highest payouts are blocked and since payouts and take in amounts are not public information, how would you get proof of such cheating? Also go check out the machines at state regulated Casinos, you will know the difference in 10 minutes.
Answer - The Indian gaming machines at those Oklahoma casinos are mostly Class II games, which are based on bingo.
I really don't think they are any worse than other gaming machines because no manufacturers offer especially low payback percentages. Usually, around 85% is the lowest payback percentage chip that will be offered.
Just because you go to a casino and continually lose doesn't mean that the casino is cheating you. If you play long enough, the casino edge will continually eat away at your bankroll, especially if you are playing low denomination machines such as pennies.
We have a Seminole Indian casino one mile from my house and I play there all the time. That tribe doesn't release their payback information either, but I don't have a problem trusting their machines.
I should say, however, that I only play video poker and the machines are all Class III, which work like a traditional gaming machine, rather than a Class II bingo-based machine.
I have been writing about casino gambling for more than 20 years and I only remember reading one story about an Indian casino supposedly have very low payback percentages on their slot machines. That story appeared in the Wall Street Journal in 2004 and it was re-posted on a different web site here - Blue Corn Comics -- Stereotype of the Month Entry
That story addresses the issues related to regulating Indian casinos and you will see that there was only one tribe that was proven to have a problem.
Therefore, I don't think there is a widespread problem, but if you don't trust the machines I would certainly advise you not to play at any Indian casinos.