I doubt they do. That was my point, they're violating it, as, in most cases, are their employers. In your example, Duke's sub-contractor contension would likely be valid. Presuming the contractor considers the drivers "sub-contractors", there's a good possibility that arrangement wouldn't pass muster, and if it did the driver would be responsible for remitting FICA. In my view, there's a lot of tax $ unaccounted for.
That is correct, but you do know that most truck drivers are considered sub contractor and the IRS has approved it. The sub contractor law's and rules and the abuse there of is one of the things that need to be fixed.