Boeing patent
If you look at that patent, it cites a long list of (very) similar patents attempting to cash in on, sorry, respond to, the post 9/11 hysteria. In all likelihood Boeing just obtained it as a defensive measure in case such a loony system were ever to be mandated and they found themselves being bent over a barrel for licensing fees. As someone else pointed out, just because a patent has been obtained doesn't mean it will ever be implemented. Nor has it.