My apologies for my lack of clarity. It's true they are regulated in a number of countries, HK included.
Civil Aviation Department - Guidelines on Operations of Unmanned Aircraft Systems (UAS)
From what I've seen here however, there is little to no enforcement of any of these rules, particularly the VLOS one.
Example:
https://www.youtube.com/watch?v=bvVu3qfADgw
And these things are on sale everywhere - toy stores and hobby stores all over the place. It's only a matter of time before something goes badly wrong, IMO.