CUHK classes

I've discovered that Hong Kongers have an interesting behavior for class. They will talk loudly during the beginning of class, despite the fact that the professor has already begun class and is speaking. Maybe about 10 minutes into the class will they finally shut up. And, as I've discovered in my graduate level classes, they (meaning about 15 people) will just go ahead and talk during class, sometimes in fairly loud voices so that it is almost impossible for me to hear what the lecturer is saying. I just want to stand up and say: "Don't you know how to behave like graduate students?!" or "Don't you have any respect for what the prof is saying?!" or "I didn't pay full-time graduate tuition to hear your conversations!" I can tolerate it if I just tell myself that it is a cultural trait of Hong Kong people to talk very loudly anywhere they go.

Also interesting to note is that CUHK has a VERY large contingent of Mainland Chinese students. It's good to hear Mandarin Chinese being spoken en masse, but really now, why so many? And where did all the local students go?