I highly doubt that their tribal membership came into play. Just because a dealer is Native American doesn't mean they belong to the specific tribe they work for. Heck, even if they do belong to that tribe, if they have multi-tribal heritage they may not collect benefits from that tribe. That means they would have no reason to preserve the revenue.

I would be more worried about someone wanting to work their way up the ranks inside the casino. However, in this specific example, they might just be a bad cutter. Some dealers can't cut.