Tonight I saw a picture of the Notre Dame (some of the members) 2012 football team. The front row one could see all the guys' genital outlines. If you don't wear the jock for support, then at least wear one for modesty. No one wants to see your junk, unless its behind closed doors with your wife, girlfriend or significant other.
About a year ago, a guy I knew at my gym was jogging on a treadmill, with no supporter, in boxer shorts. Yep, it happened. The paramedics were called he had a bad testicular torsion (somehow). It was very painful. I know for a fact he is strapped now at every workout.