Etiquette on contacting past owner of your new RV

I was contacted once by the new owner of a car that I had traded in to a dealer. I found it creepy and intrusive, especially since the guy kept bugging me about WHY I REALLY traded in the car. Really... it was about downsizing. I no longer needed the big V-8. But he wasn't accepting that reason.

I wouldn't contact a PO and I don't want to be contacted again directly by the new owner. In case of some very specific question about the operation of the vehicle, I might let the dealer act as a go between.