[thaumasiotes]

>> much more likely, they'd ask me for my address in the event they wanted to send me something

You're trying to invoke the fear that the only method of contacting your friend is to write to the last address you knew for them. That was true once; it has no particular relationship to the modern day.

Even when it was true, though, postal services were a system for delivering mail to places, not to people. If your friend moved and you didn't know that, it was difficult to contact them.