Originally Posted by
Dropline
Making sure that all passengers have a valid boarding pass when they board the aircraft actually helps to makes sure that "no people who haven't been screened are able to board a flight"
Travelling on the wrong plane is not a security issue. Travelling without correct documentation is not a security issue. They are both revenue protection issues. People being airside when they are not passengers on a plane is not a security issue provided that they have been through the same screening as passengers to get there. In fact nothing to do with the person's identity or with the validity of their ticket or paperwork is a security issue.
From a security perspective checking the BP at the door achieves nothing. There is absolutely no information on a boarding pass that tells you that the person holding it has cleared a screening process.