Lots of Muslim headscarfs on a Sunday in Hong Kong

I've stayed in Hong Kong for a week now as a tourist and have seen hardly any Muslim women wearing headscarfs so far (compared to Central Europe, say). Today, Sunday, I took the MTR Island Line to Causeway Bay and was immediately surprised by how many headscarfs there were in sight all of a sudden. I first thought of some kind of conference, because many of the women carried bags. The headscarfs were mostly colorful, as I had seen e.g. in Malaysia before. As I walked towards St. Paul's Hospital the pattern became even stronger (and then subsided again).

I was sharing my observation with three young men in boy-scout uniforms and asked their opinions. What I gathered was that these women were household workers who had their day off and spent it outside in the city. During the week they are normally not seen because they do not leave their flats of occupation. Indeed, further observation revealed that where space allowed the women sat together on mats and where sharing self-prepared food. It seemed like a Muslim-styled blend between a pick-nick and a flee market with strictly female and mostly young attendance. Some religious books were on offer too, but it main impression was this was about socializing and food.

My question is this: Is this a well-know pattern and sight on Sundays in Hong Kong (in the Causeway Bay area)? Were are the women from and what brings them here? Have I had perhaps had a random glimpse into the underbelly of the Hong Kong economy?

I am also wondering why so many Muslim women, because earlier impressions e.g. from parks have led me to assume that individual care-takers for elderly locals are typically girls perhaps from (if I had to make a guess based on their appearances) Vietnam or the Philippines. So are these Muslim women specializing in certain types of work too?