How do you define a free market? The only laws you need - fundamentally - are those in which aren't victimless crime laws. A free market is predicated on ownership, and the fundamental essence of ownership requires two cardinal premises:

1. You desire exclusive will over something.
2. You obtain exclusive will over that something without violating the preexisting will of another to hold exclusive authority over it. I.E: You didn't steal someone to get it.

If a third party (the government) can tell you what you can do with your property then it is violating your exclusive will over it. In short, the government is robbing you. Theft doesn't - and in fact cannot - simply mean I take a something from you. I could take your wallet off my counter because you left it in my home with the intent of bringing it back to you. You could borrow me your car with an understanding that I will give it back to you the moment you request it.

But if I take your car without you knowing and without your consent, EVEN if I brought it back later that day and filled up the tank, I have robbed you. It doesn't matter that I brought the car back. Theft has very little to do with the location of property and certainly rarely ever to do with having property on ones person. The moment I leave my house almost everything I own is no longer on my person, but I expect it to be where I left it when I get home.

The moment another entity can dictate what you can do with your property you no longer have freedom, because freedom requires your will remain unviolated (in a logical order of operations across time.) So I would argue that if your consent is being violated, you are no longer existing within the confines of a free market.

Now if your argument is that an employer could ask you to work 24 hours in a day or terminate employment - there's nothing intrinsically wrong with that. If YOU consent to it, then it's OK. What on earth makes you think that a third party has any right to come in between two consenting adults? Is that third party the wise and affluent intellectual, and the employee the simpleton barbarian?

The mere fact that freedom requires violence utilized to protect from things like murder, rape, assault, theft, and fraud means that you do not need to really worry about things like labor laws. So long as an employer cannot force you to do something at gun point means you get to consent. In addition, so does everyone else.

I'm not working for a business that forces employees to work 24 hour working days. I'm also not BUYING anything from those businesses, would you?

And remember that if a business hides these facets from the market that fundamentally is what fraud is. Fraud, I would argue, is at its core about trying to get someone to consent to something by purposely (or by way of negligence) misleading them. I KNOW a lot of people wouldn't work for me or buy from my business if they knew I employed children, so I will hide that fact - that's fraud.

And since you cannot live in a free society where there's rampant fraud, there would need to be individuals ready and willing to use violence against it. Frankly the proper answer to such a thing would be to just apprehend the owners of the business directly. The fact that we treat companies like individuals is nonsensical. If you want nefarious acts done via business to fade away, start imprisoning the owners/CEO's for what their businesses do.

The good and just need not permit the machinations of the sinister. If someone shows up to your home to threaten you and your family, the just and proper answer is to end them. Violence is in no way intrinsically evil in its own right. The sword - it can be used in the defense of the innocent and goodly, or to enslave the masses.