The government already provided a number after they were asked by The New Paper (who appears to read this forum).
The answer is 17. (believe it or not) And they went on to claim that most of the cases were infected by their employers and not vice versa (how they know this for a fact nobody knows, did the virus tell them?)
You are correct about the maids being young and the potential asymptomatic cases. There is also the possibility of suppression of symptoms. I am not against maids, but the question remains why there are still so many unlinked cases "pending contact tracing" even after 3 weeks of CB. The answer is simple. There is deception out there among confirmed cases and untested cases suppressing their symptoms. Other than people visiting prostitutes and having affairs, another group is people having illicit relationships.
Yesterday alone there were 30 cases. The gahmen needs to provide details as to the number of them are maids. Also not to presume that the virus was transmitted to them from their employers. Most of the maids are young and thus could be asymptomatic or the symptoms appear much later. The gahmen cannot be complacent and should conduct tests on everyone in the household whenever one member is detected. Quarantine is not enough because of the high ratio of asymptomatic cases. Otherwise the community transmission will become uncontrollable.