I was looking at availability on BCD (and another site non-public site) for SFO-CPH that is showing R class before Y, suggesting that it is in business. It was zero until around 48 hours before departure when business dropped from C9 D9 to C4 D0, but R became R3 and then R4 hours before departure. (So it shows C4 R4 Y4, etc...) This suggests to me that it shows availability for paid/ auction upgrades. What do others think?

Historically, R was a non-revenue booking class, which would never show up on any availability tools.