What does union cards have to do with you exploiting your workers? And like I said if your workers educate themselves on the laws they could bring litigation against you. So I wouldn't be so arrogant if I were you.
Corporate legal dept isn't going to allow contractors to violate state labor laws. Whatever they are doing has been shaped into it's present form by numerous litigations and represents what's deemed acceptable by the courts. As crappy as the pay is, compounded by no benefits, it's legal. The only people who could possibly take pride in what's happening at Ground, however, are those who are making good money and considering how they're making it that's nothing to be proud of.