Key legal question
Whether X. was subject to customs control and had a duty to declare the dog as driver of the vehicle
Extracted holding
Yes. As the driver transporting the animal across the border, he was subject to customs control and had to take the steps required for declaration, regardless of ownership.
Extracted reasoning
Customs liability attaches to the person with a factual connection to the physical border crossing, primarily the driver. The legal owner is irrelevant; responsibilities may cumulate.