I would say yes, especially if the road is posted as a private road.  I have also seen warnings about people going door to door while seeking to figure out who is not home during the day so they can break in.  On the other hand, last year when someone questioned people who were going door to door on our private road, it turned out they were from Fidium, signing people up to get connected to fiberoptic internet - so there are cases where it's someone you might actually want to talk to.  You can always ask for credentials.

Delivery trucks are different - they would be considered to have been invited.