As I said upthread, the easiest thing to do is enforce the minimum number of segments on RJ and/or to not allow Oneworld Emerald qualification via segments. I don't really think it's profitable for RJ to be paying for lounge access whilst IAG only pays partner FFPs a tiny amount for those cheap Y domestic flights people are using to reach/retain status.

The status match offer has been running for awhile. But it's only been a year since BA elites started realising they needed to move elsewhere. So people who matched back then might now be realising that they are short some segments to renew status.