I'm fully aware that my second segment WILL be cancelled, but my original question was in regards to WHEN it will be cancelled. Obviously it wont be cancelled before I fail to board the PDX to LAX leg. The question was, will I be able to check my bags at LAX for the LAX-SYD leg if I show up there before my PDX-LAX leg (which I wont be on) has departed?

I think the answer is maybe, if one is very lucky...