That's a neat idea. I can imagine most of the potential problems can be solved by requiring a credit card to sign up, and image recognition software - if the po

That's a neat idea. I can imagine most of the potential problems can be solved by requiring a credit card to sign up, and image recognition software - if the pod is supposed to be empty, then the onboard camera can check if it really is (could also measure the pod's weight, use infrared and ultrasound "vision"), and alert a human operator otherwise. Bombing a 4 person pod does not make much sense to me, since there is not that much damage that can be done underground, with the exception of starting a bomb right beneath a huge building. I'm not sure a potent enough bomb can actually be carried around though.