Hate to play devil's advocate, but it sounds somewhat similar to what Israel does with their airports, but leveraging technology to identify all details (and more than a human could reasonably do), rather than training individuals to do the same.
Methods, deployment (in terms of location) and data retention are obviously the distinguishing factors here.
http://news.ycombinator.com/item?id=1024850 for an article on it, from around two years ago.