CX have this developed to what I feel is an overdone art form. They have First and Business priority tags, which are attached to the bag. The computer then generates an additional small validation sticker for the priority tag, using the luggage tag printer, which include details of the flight number and, in large figures, the last three numbers of the main baggage tag number... They do usually work though!

Best I have heard of, but not experienced, is NH at LHR, who supposedly have dedicated luggage team supervisors for their single daily flight, ensuring baggage gets to the reclaim belt rapidly and that priority tags are followed.