Yeah, it's a mess. But a non-friggin'-stop flight, and I was the only one on the flight whose bag didn't turn up. I watched the bag go through the scanner after which it got loaded and wheeled off with the rest of its "mates".
It didn't make it on the BCN flight tonight. That they know, which makes me think the tag is torn off, since they have no idea where it is, except that it wasn't on the next-day (today's) flight out of JFK.
As you said, there's always a first time. Maybe your bag got the freedom search, maybe it fell off somewhere...give it another day. These things really do happen & typically have happy endings. Well...as happy as they can be with the bag arriving a week late.