With our diverse society, it would be all to easy for these guys to melt into the landscape. That is why I take a hard look at these people when the FBI releases pictures of them. I treat these pics the same way I do with the "missing child" cards I get in the mail once a week. If I have their image present in my mind I am more likely to recognize one if I happen to see him. It is important that we all not be paranoid, but always be aware of the people around us. We are the first line of defense.
Stay safe.