Well I often fly a bunch of B fares and occasionally a Y during the year but I only see it a few times per year. If you have a high fare sometimes and I cannot figure out when or how you get Coach Select Bonus.

It gives you:

1. 750 miles
2. A PF on your boarding pass so you can board with Elite (as if that matters for me)
3. Occasionally WP pass

Beats me how it happens, I just wanted to know since for me it was not the fare as I did not get it with OLCI but it seemed to be the flight.