Me, too, I'm a sucker for science that I cannot possibly understand. Always impressed by it.
I gotta say, I have no idea what is the ultimate meaning of this paper. It was spurred, like other studies, by the discovery of the planet, Sedna, and its odd orbit. My brother got involved because he's studied and modelled planet formation. I think that's his advantage over other observers of Sedna.
Btw, great screen name!
In a nutshell, it means that Sedna's existance in that particular location is an aberration--there is likely no model of solar system formation that will account for it being where it is, so given that fact, it examines the likelihood of a Sun-Star encounter leaving the matter that became Sedna, or Sedna itself in it's particular orbit.
Interesting that capture of planets is possible. There are probably planets all the way to the next star and it might be hard to say which star some of them belong to. There could also be planets sailing through space at high speed that belong to no star anymore. One of those could fly through the solar system at any time and there would be no warning. It could even hit something with energy far in excess of any asteroid hit that comes from within the solar system.