#3
I highly doubt that. I spent basically 3 years playing with M1091A1s, a self propelled version of the towed 105mm weapon described in the article. The firing rate of a six gun battery in those years may have reached several hundred on a typical training mission a few times a year. No where enough to hit a million a day.
That said a 155 round alone is basically inert. It has no way to detonate without a fuse. In my day there were three fuses, PD, timed and proximity. PD, point detonating, goes off when it hits something. Timed goes of at a set time, fixed at the gun, after firing. Proximity goes off at a set distance from impact, basically determined by radar from the fuse. I'm sure technology now provides methods I'm not aware of. Nevertheless my point remains the same.
There is no explanation for a round exploding mid-flight as the investigation finds. Was it wise to shoot rounds over an interstate highway? No. Is there an explanation for the detonation? No. Do soldiers need live fire training? Of course. How is this incident prevented? Point West instead of East.
#3
What if you and your authoritarian pals go f*** yourselves.
How folk transact their necessary business is not for your voyeurism. Try learning what the First and Fourth Amendments have to say about your desired perversion.