1. Has Sze committed any criminal offence by posting her message on the Internet?

It is an offence contrary to Section 147 of the Crimes Ordinance (Chapter 200) to solicit for any immoral purpose in a public place or in the view of the public.

The maximum penalty for the offence is 6 months imprisonment and a fine of $10,000.

The information Sze posted on the Internet presents as an offer of sexual services in return for payment. Though the uploading took place in private, the information is now available to the general public or at least those members of the general public who use the Internet. Sze’s message is likely to be regarded as "in the view of the public". She may has committed the offence of soliciting for an immoral purpose contrary to Section 147 of the Crimes Ordinance (Chapter 200). (See HKSAR v Chan Yau Hei [2011])

2. If the actual age of Sze was in fact 15, but Ming genuinely believed that Sze was 17 years old as mentioned in the message on the social network, has Ming committed any offence by having sexual intercourse with her?

Ming has committed the offence of “unlawful sexual intercourse with a girl under 16” contrary to Section 124 of the Crimes Ordinance (Chapter 200).

The maximum penalty for the offence is 5 years imprisonment.

Once it is proved that Ming had sexual intercourse with Sze and she was under 16 years of age at that time, Ming is guilty of the offence. Sze’s factual consent is irrelevant because she is under 16. Ming’s belief that she was 17 is similarly irrelevant. The offence is having sexual intercourse with a girl under 16 years of age and that is what Ming has done.