It's a bit of cliché to think because it's chinese related they just can pull a domain name right out of your hands. (of course China could start a world war for all that matters, lol, and the usa could invade canada if it wants to, but still very unlikely to happen)
There is a set of rules and striking an .hk domain has the same probability of any domain that deviates from its registration rules. Either it to be .com .net .fr .ch .in .hk
When a domain is used in violation of it's registration rules the responsible domain authority can retire a domain.
If handing over, lending, selling to a new party and that party agrees upon the rules related to that domain there shouldn't be a problem.
There are no specific restrictions on transferring a .hk
Stick to the reg. rules, that's all.
Example from HKDNR Registration rules showing under which conditions a domain name can be transfered:
11.1 Procedure for transferring a domain name
You (in this clause referred to as "Transferor") may transfer the registration of your Domain Name to another party (the "Transferee") in accordance with the provisions set forth in the Rules and subject to clauses 11.2, 11.3 and 11.4, provided:
(a) the Transferor and the Transferee mutually consent to the transfer and jointly execute a Transfer Form as set out in the Rules;
(b) the Transferee:
(i) complies with the eligibility requirements set out in Rules for the Domain Name that is being transferred;
(ii) agrees to be bound by the terms and conditions of this Agreement; and
(iii) pays the prescribed Fees as set out in the Rules; and
(c) the Transferor or the Transferee pays any Fees that are owing and due to us before the application for the transfer; and (d) the Domain Name registration is not being challenged by a third party or pending dispute resolution in accordance with the Dispute Resolution Policy.
Once the transfer is completed, the Transferor's rights and obligations associated with the Domain Name registration shall be transferred to the Transferee.
The full registration ruling can be found here
http://www.hkdnr.hk/eng/legal/registration_agreement.html