So here's a fun fact about the "security" laws China forced down Hong Kong's gullet recently: they apply to everyone on the planet. They're vague and "subversion" pretty much includes anything you want to include. It's anything that makes the Chinese government or Chinese officials look bad, basically.

So, if you're not even a citizen of China and you're sitting in Europe or the USA and you make some critical post about China to such a degree that the Chinese government deems it "subversive" and you then make the mistake of transiting the Hong Kong airport, you can be arrested and sent to the Chinese mainland for trial.

Interestingly, Qatar has a similar law but it's more limited in scope at least. If however you have a job in Qatar, I'd highly suggest you don't say anything negative about Qatar or the royal family, even on a Facebook post while in a completely different country. People can and have been arrested for this.

Also, Qatar is one of the few countries that require an exit visa to leave the country so think twice about working there regardless of that.

But I digress. I think it's fair to say that any notion of Hong Kong independence or sovereignty is a thinly-veiled illusion at this point.