Yes, pretty well being sent to random people. That is if driving around town, listing down the streets and addresses, then making a "territory" and sending letters to every address is random.
Of course no effort made to find out if the person associated with that address is living or not, or if they still reside there or have moved, or if they may have divorced and remarried.
What could go wrong with that kind or "organization"?
I would guess that a large majority of the letters get returned as undeliverable, and the rest just get put in file 13.