The Hong Kong Governemnet reminds that:

Possession of stunning devices is governed by the Hong Kong laws and is a serious offence, because stunning devices are defined as “arms” under the Hong Kong laws. Offenders are liable to a fine and/or imprisonment.

The Hong Kong authorities are strict with the enforcement of the said Ordinance. All hand-carried and checked in luggage of passengers are subjected to security screening in the airport terminals; this applies to passengers coming to Hong Kong or transiting via the Hong Kong International Airport.