We were aware of it when it was over Montana, which is a very sparsely-populated state. Is it really that hard to shoot something like this down over such a territory? I have no way of knowing, but I'd think they could bring it down without risk to human life. The main thing I'd worry about is that it might have some sort of unannounced payload that would be spread widely if it were exploded mid-air. But I didn't hear anyone talking about the risk of biological/chemical weapon possibilities as the reason to not bring it down sooner.