Welcome to Las Vegas. The City of Lights. Sin City. Glitter Gulch. The Strip. From the first casino that sprung up out of the sweltering Nevada sands, no amount of glitter and glamor has been able to completely cover up the grime that lies beneath. Las Vegas has always been, simply put, a mob town. Everybody knew it then; they still know it now. But gangland central with mobsters ending up as pasta sauce on their own front windshields doesn't tend to bode well for business. And business, my friends, is what it's all about.
And that's why, before any real government agency could be installed, the good ol' boys more or less formed their own gaming agencies to regulate each other: the Nevada Gaming Commission and the Gaming Control Board. True, both agencies were adopted as state departments and the members appointed by the Governor of Nevada, but since the 20's no governor has gotten elected without the thumbs up of the labor unions, and the unions aren't just looking out for ol' Joe Teamster anymore. That way, the people who need to get paid do.
Now, a little known fact about Las Vegas is that the several block long road that makes up the Vegas Strip is not actually part of Las Vegas city. It is unincorporated county, and will remain so so that no city taxes or laws apply to the strip. This leaves the Casinos at the mercy of only the regulating agencies and the hands-off county seat who has always turned a blind eye. And this in turn allows the casinos and their friends at the twin agencies to police themselves.
Some may call it a conflict-of-interest. Others may call it corruption. But in the end, self-regulation goes back to one of the basic tenants that ruled the west when the west was still young: plain old vigilante justice.
The Great Mutant Heist of 1983 was known only because of its enormous failure. Though it had long been suspected that Mutants were using their powers to pull the wool over the eyes of the casinos, but it would take a very public fall to send out the warning and show the federal agencies (FBI, IRS, etc.) that the Nevada state agencies could hold their own against the problem. Since strip casinos are in unincorporated Clark County, those who are employed by casinos are allowed to be armed, loaded, and discharge weapons to secure property and the safety of patrons. Since the state agencies are a sworn and policing agency, they can make arrests and assign penalties and press charges on law breakers.
Mutants beware. You mess with the mob, try to use your powers to make a little extra cash at their expense, and you better be prepared for what's coming. First offense? They'll let you go freely. Out of town, that is. Second offense gets you the Collar. Power dampeners are all the rage, these days. Third offense? Let's just say they aren't into no cozy prison cells, unless you're one of their white-collar pals. Coulson Prison doesn't seem to care too much where its funding comes from these days. They're more than happy to cooperate as long the cash keeps flowing. And the other agencies are more than happy to keep looking the other direction with regards to those few unlucky individuals who just never seem to turn up at all.
That said, the average person may not even be aware of the shadier dealings going on beneath the neon lights, and not all mutants are viewed as threats. Many of them have found positions as bodyguards or surveillance at casinos, protecting investments and making sure others aren't cheating the House. As long as business continues to thrive, the mob isn't about to make too much of a scene about the mutants unless forced. No need to attract SHIELD's eye unnecessarily.
There are other contenders for power within Las Vegas, too. The Brimstone Society, while containing some mafia members, has goals all its own, some known only to the privileged inner circle, and they are slowly wrapping more of the city around their fingers. Hydra and AIM have been making nefarious plans in their hidden bases, evading the watchful agents of SHIELD as they do so, and the Brotherhood and X-men are both attempting to gain a foothold in the city, to sway the mutants there to their conflicting causes.