Judging by some of the stuff I've seen others carry through HKIA security, I'd be surprised if CX bothers checking anything at all.

However, I've noticed that outports are generally more strict about cabin baggage than HKG.

Especially if you're travelling on KA flights using smaller aircraft, you should expect that oversized baggage will get targeted for check-in at the gate. Same thing will happen on AA domestic flights as well.