Whenever I see someone acting crazy or behaving oddly in public, I intentionally maintain eye contact. I try not to loom intimidating, but ignoring them makes me more vulnerable to their potential actions. Most people do the exact opposite and will even turn their backs to the person acting crazy.
https://www.youtube.com/watch?v=29WwpU7GzSQ

Has this debate been settled? Should you look at them and mentally prepare for a fight or to use your gun or should you look away and pretend they don't exist?