Just wait till some screwball does attempt damage by those other modes. Then everybody will have to prove they are safe beforehand. It is the philosophy. It is the idea that safety depends upon knowing everyone's intentions. Odd that we're nearly at ten years since a bomb took a plane down in America, yet the "professionals" still claim the safety measures are not enough. I still think our doors are way too wide open to the world. And not just here. We've become very rigid in thinking the more travel the better. Where is the evidence that the vast increase in travel has led to more peace in the world? I watch Al Jazeera and Deutsche Welle every day, and it becomes tiresome how much of the world is a wildfire of human violence. People may like people, but peoples definitely do not like other peoples. Even coming to America has not made Islamists more peaceful. Look at that guy in Yemen who preens himself as he incites more killing?