I’m not sure many tourists are traveling with quantities sufficient to qualify for that treatment.

More likely you’ll face a fine or a strong talking to if you get caught at the airport with some small quantity of pot.

Not really sure where you see the disagreement?

Relies on OWL which does have specific hardware requirements

Not necessarily, EU car registration usually provides information about who the car is registered to, not who owns it. These are two different things, of which only the first seems like something the government actually might need to know.