To add, a person from Hong Kong on a different post, offered this piece of insight, which I feel is very astute.

"1 Oct National Day is coming. Beijing will not be happy to have another 2 million demonstration on the big day (70th anniversary)."

With that and the Hong Kong airport being the world's 8th busiest, there is lots of money and pride on the line for the China Govt. They will go in pretty soon.