According to one account I read, the largest foreign population in HK is Filipina domestic workers. Sunday is their collective day off and they flood into Central for picnics and general camaraderie, taking over much of the public space, sitting on blankets or mats or whatever. Below are a few shots I got on the Central walkways. That's quite a clash of worlds below... Western tourists on the left, emigrant maids on the right.
My understanding is that although they earn a lot more money than they could at home, these people are often not terribly well treated in HK and subject to a fair amount of discrimination - their status and treatment is a live social issue, with some controversy lately over a proposal to make them eligible for permanent resident status (which they currently can't get no matter how long they stay, if I understood the article correctly). I've heard of a couple of high-profile cases of abuse, one of them allegedly involving a big movie star (I forget which).
I like these makeshift pods from cardboard boxes that allow them to sit outdoors in the public space while keeping some physical separation from the rushing crowds, for the convenience of both.