Apart from a transfer to another vehicle or to another mode of transport, dangerous goods come off a road vehicle only when the consignee, or someone acting for the consignee, is there to receive them, or when the driver, prime contractor or consignor has agreed with the consignee that the goods will be left in a secure place and they are unloaded there.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.