I doubt I would be able to see him in person without reacting at all. The "stare em down with a smile" approach is way classier, IMHO.
You can if you practice beforehand by repeating the same mantra over and over which is: I am calm, cool, and collected.
Then picture yourself running into the OM and giving him the chit-eating grin when you glance at him while continuing walking in the opposite direction with your back ram-rod straight in your unique Rzr swagger. When visualizing, feel the emotions, feel the scene, feel the OM's presence, and feel yourself being confident.
I find that visualizing helps prevent one from getting into a clusterf*ck situations and prepares you mentally for the encounter.