Thanks for the clarification, Oldtimer.
Just to elaborate, negotiated, signed and work done outside HK (and ideally paid outside HK and in a foreign currency) then... it may be not subject to HK tax (but then likely come onto someone elses tax-radar).
Going on a day trip to Macau to sign your contract that was emailed to you doesn't really count.
Or worse still you fall into a personal (as opposed to your company) world wide taxation regime - e.g. UK after 180 days/tax yr (avg 90/yr for 4 years) with obligations to file therafter whether you are there or not. Try getting off that tax radar. (Ignoring immigration status)
More than a few people have had to abandon a nice little earner because of this rule...