What's a random stranger anyway? I'd imagine that all strangers are random, right? By definition, you have no acquaintance with them, so you can't predict them. Anyway, I thought it was an oxymoron. Maybe I'm just being random ;)
By following your own logic, it wouldn't be an oxymoron. It would be a pleonasm.
Pleonasm. That's a new word for me. Thanks.