Distribution fraud would likely occur before the goods are loaded onto the truck.  A common distribution fraud would be to exclude the loading of one or more boxes of goods, and falsify the manifest and/or bill of lading.  When the customer receives a short-shipment, the supplier would blame the third-party carrier for the loss.

Another possibility is that the third-party carrier is responsible for the loss of goods once they are in their care (loaded on the truck).  The possibility for this increases if the goods are loaded and unloaded at distribution centers or cross-docks during the trip.