The proper term for billions-billions...
I imagine they're right and that the evidence for it would be pretty conclusive -- something simple, like the trajectories of the objects were almost opposite each other.
I think a better lesson to take away is: "Holy mackerel, there are a lot of large objects which can strike us at any time, and we're only now scanning the skies enough to get any kind of a heads-up before the next Tunguska.
I've seen polls indicating the public thinks Armageddon is real, and that we have the ability to "just blow an asteroid off course with a nuclear rocket." In fact, we don't. If we ever detect one of these Big Boys on an intercept course, our best scientific/military response will be "Go to church."
In response to Expert: Meteor Shower, Asteroid Passing All a Coincidence.