Last year, as a gift I got a set of plastic boarding passes arranged to make my Rapid Rewards #. Framed up on the wall now.

Odd thing is--my first WN flight was Nov 2001. I only ever recall numbered A/B/C plastic boarding passes, never these numeric BPs.

This was before online checkin, and the loophole we found for better boarding was that the A boarding passes were divided into three distribution points. If the checkin counter gave was out of A/B and giving group C, we could often get a B at the skycheck podium. Then, after security, we knew to ask the gare agent what passes they had left. Few checkin at the gate, so that often got us ta trade to the "A" group.