Securing Pallets of Sod

We have seen an increase of trucks hauling pallets of grass that have tarps partially covering their loads. The pallets usually sit 8 to 12 inches from the header board (requiring 2 straps in the first 10 feet) and have every other pallet of grass strapped. As we understand, if the pallets are fully covered by a tarp, then the individual pallets become one load, and would need to have 1 strap every 10 foot or fraction thereof. In the attached photo the tarp covers the top 8 to 12 inches leaving the rest exposed. Each pallet weighs approximately 2500 lbs. Given the scenario in the photo, if the load were to shift what would keep the unstrapped pallets from falling from the vehicle. There has been discussion amongst the different agencies here in North Texas on whether or not each exposed pallet would need to be secured via a tiedown/strap.

Please clarify if the partially tarp load in the attached photo would constitute one load requiring one tiedown for every ten feet or fraction thereof, or if each indiviual pallet of grass would need a tiedown.

Issue clarification on the above issue so that uniformity in enforcement can be obtain.