For what it's worth, I first heard the term many years ago used to refer to either a one night stand ("picked up a rando") or a previously unfamiliar housemate

For what it's worth, I first heard the term many years ago used to refer to either a one night stand ("picked up a rando") or a previously unfamiliar housemate ("rented a place with a rando from Craigslist"). It certainly is dismissive in the sense that it communicates "this person was of no special importance to me", but sometimes that's an appropriate thing to communicate.