I think all this body searching is more political than useful- it makes people think the government is doing something to protect them.
But in reality- re-enforcing the cockpit door has done more to prevent hi-jacking than anything else. If the hi-jackers can't get into the cockpit they can't take over the plane- period. Threats to shoot victims or blow up the plane won't work because we know if we follow their instructions everyone would die anyway.