I don't care who my rivals are. If they are proud of their school and want to wear their gear, so be it. There is no scenario in which I'm going to say "Utah stinks, go Cougs!" to some random person I don't know that is sporting their gear. I'm sure there are BYU people that do this to Utah fans but I haven't personally witnessed it and I've been the recipient of numerous weird encounters like I described.
Do I good-naturedly rib my Ute friend fans once in a while? Of course I do, as do they to me. Which is fine because we are actual friends – not random strangers on the street.