Yeah, the possibility for a hyperbolic trajectory was surprising. I wonder if it's really roughly a 1/1000 chance in 200 years, or simply a freak artefact of the simulation. This is sort of related to something we see in meteor observations, since typical meteors, like the Tesla, are inner solar system objects in an orbit with Earth encounters. Very occasionally, orbit calculations give an eccentricity > 1 (and are difficult to explain with inaccurate observations). The question then is, especially when the orbit is barely hyperbolic, is whether it's an interstellar meteor, or a local object that has been slingshot gravitationally. One could think that if such hyperbolas form frequently, the solar system would have emptied itself of dust and meteoroids long ago. But on the other hand, the solar system was formed with an extremely high number of small objects.
NIL DIFFICILE VOLENTI