Wharvey, Good question, the answer for HKG is:

- Passengers arriving without the required documents or with
incomplete or expired documents, may be refused entry and a
fine of HKD 10,000.- will be imposed on the transporting
carrier. The carrier will be responsible for returning
passenger to point of embarkation or place of origin.

Again, this sort of thing is quite easily avoided if you have your brains about you.