Have there been any data points about separate tickets on one PNR?
AA's policy for instance is to treat separate tickets to oneworld on a single PNR as through ticketed (for both checked baggage and misconnects).
AC's policy is clearly that it won't work (unless they are AC, 8P, or 4N tickets), but I wonder if in practice it makes a difference at check-in if that means the agent sees the final destination on their screen.