Sorry for reviving this old thread, but I have a similar question.

I'm flying next week from YUL to HKG via YYZ in Y as a SL for the first time through a ticket purchased straight from CX that includes the WS codeshare service from YUL to YYZ (I used to purchase them separately).

Will CX staff in YYZ attach priority tags if WS tags it all the way to HKG? Or will WS have them in YUL?

I, too, am in a big rush to leave HKG asap as I have a commitment shortly after the arrival time.

Thanks.