Reading more into it and reading OneMileatatime blog, I am wondering whether passengers are using their oneworld status on one airline to access the lounge but crediting the points to American Airlines. Not that anyone should be doing that.
I hope the change doesn't affect Qantas Club members but looks like there is some tightening of the rules.
Why should people not be doing it? The GDS specifically has fields for FQTV and FQTS, so you can use two different FF numbers in your reservation; one for earning benefits, and one for status benefits? In fact, the *only* Airline staff i've ever found who know how to do this successfully are the AAngels at the T4 LAX A/C!