“Working in Hollywood, people ever wonder why USPS does not deliver to celebs addresses? There is a ‘private service’ which does that.”
I suspect most celebrity mail would be fan mail. A publicity company would probably send a reply with a picture and short letter thanking the fan and telling of any upcoming film or record release (to help cover the cost of the reply).
Almost everyone in the biz knows this. I even know a few of the drivers. USPS doesn’t even operate in Malibu or Mulholland Drive. They are “registered” but almost no USPS truck driver ventures there unless you have a restaurant which caters to celebs etc.