They are on the street. Street signs are ubiquitous. If I pass by a home with 29 on the home or mailbox, I’m certain I could ascertain the street name in a matter of seconds by looking at the sign at the next cross street.
It’s just seems kind of weird to think that putting your street name on a mailbox is giving away too much information. Particularly in the information age when all you need is an idea of a persons address, their name or even just a name & the city they live in & with a couple key strokes you can find out who they are, their complete address, their marital status, their mortgage holder as well as their mortgage balance all through public records & Google searches.
I prefer to have a degree of anonymity with regard to where I live, even though the postman probably knows.