Hmmm... Good point about the luggage. Sometimes when I do this all I have is carry on, which of course means no problem. On my last trip however, they simply sent my luggage on the first available flight. It was waiting for me at the CP baggage counter in Vancouver. I could have gone on that flight as well, but I would have been in economy.
However, I don't believe they will let you do that on trans-border flights. Might just be on the LAX segment, or maybe both. You should probably call CP and ask. I'm just not sure about that situation.
Regards,
Ken Hamer