Schellville is also a privately owned but PUBLIC USE airport, I believe owned by the same people who run a company on field that offers vintage bi-plane rides over the Sonoma and Napa Wine Country (charging exorbitant amounts of money for rides in Stearmans and a T-6. I still love the company though and would love a ride.
Whether or not they own the airport, they have exclusive rights to use the north-south restricted runway 17-35, and operate their aircraft NORDO.
So with this particular place, see and avoid really comes with the territory.
And as far as I heard, the Glastair pilot did NOT use the radio.