I ride the TriMet light rail in Portland, Oregon at least twice per day, sometimes more. Frequently - several times during each ride - a recording plays which

I ride the TriMet light rail in Portland, Oregon at least twice per day, sometimes more. Frequently - several times during each ride - a recording plays which says "Report suspicious items to TriMet personnel, or call 9-1-1". Several times per ride, every single day. Is this really necessary?