If I remember correctly, as there was a lot of info given by the inspector, soil is collected and sent out to check for nematodes, and before sending an order to a state that requires a nematode check, the seller's state inspector has to inspect the plant/plants to be shipped. Imagine holding an order of plants waiting for an inspector to schedule their time and travel a long distance to okay an order.
Also, any plants purchased for the garden must come from
an inspected and licensed origin, and proof of this has to
be affixed to the box and purchase records kept with the inspection/licensed
stamp included for the inspector to review.