All pilots who know how to fly in the US know how the US system works, which is always exactly per the AIM and order JO 7110.65T.
I commend the Canadians for making their policies clear.
HKG ATC (and, as a result, CX), as Unionist2010 states, can't get their heads on straight. That's why all CX pilots always question everything, all the time.
HK ATC doesn't even say, "Line up and wait," but rather, "Line up." Go figure.
I think the SAFEST, based on the near collisions in HK a few months ago, course of action when cleared to an altitude not complying with a SID/STAR restriction is to question it. Who knows if another airplane might be at your level because of the ambiguous statements in the AIC cited by Unionist2010?