Among the most fantastic things ever produced in Hollywood are their financial records. Practices are outrageous, and this isn't exactly unknown.
But has anyone ever heard of a studio being audited by the IRS? Maybe it has happened and I missed it. It sounds like it could be fun though, watching disgustingly rich people poormouthing, claiming that they're not making any money.
It would be politically dangerous to take on movie studios though. These guys put on elaborate fantasies for the public for a living, and politicians wouldn't stand a chance against them. We'd hear braying about the 1st Amendment too, charges of being "politically motivated", etc.
So for practical purposes, Hollywood is probably above the law.