Unless the law was to state that an order has to be transparent from the shipper through all the hands to the truck, it is useless. Far too much grey area in between. Your only friend in this may be the IRS in terms of wanting to collect every penny they can of the transaction from each parties hands. The IRS knows they are not getting their fair share from Freight forwarders, 3PLs down to the truck. But that would all add more complications.
I have mentioned this before, a friend of mine worked at a rigging company in the office. They did heavy haul oversize stuff, but got a good amount of other freight they would outsource. The loads in reference to this paid $3800 on a flatbed legal size. First company took $1,000 off the top, forwarded it to a broker separate from them. That broker kept $1400 & posted the loads on a load board for $1400 to the truck & they all got moved.
So the real choice is to hope for a bunch of new complicated laws to strangle everything ~OR~ beat the bushes for your own freight direct. Personally am not a fan of more laws & working to get my own stuff. It is tough to do, but you can see what can happen by the above example.