On Mon, 04 Dec 2017 18:50:12 +0100, Paul Schlyter wrote:

And that follows directly from elementary celestial mechanics,
nothing suspicious here.

What is suspicious was that the course change was acute vs obtuse. In other
words, a random distribution of incoming velocities would give greater
chance of objects passing so far from the Sun that their trajectory in and
out are almost co-linear. (i.e their velocity is barely affected.)

The consenus here seems to be that such objects are, in fact, more
prevalent. We just cannot observe them unless they do pass close to the
sun.