I believe that if an employer is aware that their soon-to-be-former-employee is planning to leave HK, then they are obligated to ensure that said employee has cleared his/her tax obligations with the IRD before issuing them with their final paycheque.
Is the loophole then with those unscrupulous persons who don't inform their employers or the IRD that they are planning to leave HK, and in that case the company, in all good faith, issues them a final paycheque and is none the wiser until the end of the year when it comes time to prepare the (ex-) employee's tax returns?
In that case is it true that the company becomes liable for the tax obligations of the former-employee, who has effectively managed to escape the IRD unless they return to HK? What are the means, if any, available to the company to stop this abuse - if it is indeed so easy for an ex-employee to simply accept the final paycheque and take a one-way trip out of town, and assuming as well the the IRD may only have some provisional tax and MPF contributions to hold onto?