In the early 1950s, at the height of the notorious McCarthy witch hunts, many Hollywood figures were brought before the House Un-American Activites Committee (HUAC) and asked to name communists with whom they were acquainted: left-wing actors and directors whose careers -- and lives -- were subsequently ruined (many committed suicide). The actor and director Leo Penn, Sean Penn's father, was one of a handful of Hollywood luminaries who refused to cooperate. Elia Kazan, on the other hand, was not.
One day, Leo happened upon Kazan while the latter was filming The Last Tycoon near the Penn home in Malibu. As Sean Penn later explained: "My dad is a very warm, polite person and Kazan said hello to him -- and dad just walked by..."
[At the height of the scare, the Cincinnati Reds changed their name to the Redlegs.]