This has more to do with one's personality (leader vs. follower), than it does with your desire to help someone else. People who are used to leadership roles t

This has more to do with one's personality (leader vs. follower), than it does with your desire to help someone else. People who are used to leadership roles tend to project an aura of confidence, which automatically helps in these type of situations -- whereas someone who is always very passive may not project enough confidence, and therefore won't be as effective, thereby reinforcing their notion that they can't do anything to help anyway. One thing, though, if you are a leader type, and need more hands involved. Instead of making a general request to the crowd, point at a particular person, and say something like "You in the green shirt and the cell phone -- can you call 911?" "You in the yellow jacket, can you help direct traffic?", etc.