I really do not know the details of the agreements between the airlines and the airport operators, or among the airlines. I only know that NOTHING is done our of courtesy or kindness. If for example CPH charges SAS for each passenger that uses the fast track, like they are charging KLM, Air France etc for the same service, I well understand that SAS limits the privilege to its best cutomers: C, Y and EBG. I suspect that in other airports there are different arrangements. I addition, probably, unlike the preferential check in and the lounge access, the security fast track access privilege is not covered by the *A bylaws.

Again, SAS is (well, is supposed to be) a company that wants to make a profit, like CPH: so SAS looks after its customers, and CPH sells its services, like the CPH apartment lounge to various airlines