I doubt I'd ever see him in public, since our city is huge. We also haven't discussed the possibility. However, if we were to see each other, it would really depend on who I am with, and who he is with. I'd not want him to say hi if he were accompanied by anyone at all. And I'd not want him to acknowledge me if I was accompanied by certain people, with others it would be fine.

So I'd expect him to certainly not start the interaction, and if I were to acknowledge him, to be smart enough to just say something like "hi, good to see you" and not start talking to me more... which I'm pretty sure would be what he would do.