In the past, I also thought that the maid will go back home not later than 14 days after termination. But we are WRONG, the immigration department is very generous to maids since they allow maids to stay in Hong Kong and no need to go home if the employement agency found another job for them. The immigration is doing things against what they told the employer.
I once rang up the immigration and complained that because they allow the maid I terminated to stay, she always rang up my home and disturbed my daughter, but the immigration said this was not enough evidence to tell that they allow the maid to stay, they asked me to collect the maid's partport to proof this before make any further complaint, this is totally UNREASONABLE, how could I get the pastport from the maid I sacked??
So don't expect they will return home straight away, you may see them on the street later on.