We might as well all face it that in today's age, crap like this can happen any where. Instead of focusing on airports all the time for security purposes, policies and divisions need to be set up to do more look out for the big out takings such as this marathon. Maybe then the money being spent on this type of work would actually be going to it's intended purpose. With that said, we could never catch it all I'm afraid. We better hope these bombs weren't made with water! They'll spend more time trying to make bans on water and make it deadly, not the operators!