Okay:
China rotated troops in its People’s Liberation Army garrison in Hong Kong on Thursday, days before protesters planned to hold a march calling for full democracy for the Chinese-ruled city after three months of sometimes violent demonstrations.
Chinese state media described the troop movement as routine and Asian and Western diplomats watching PLA movements in the former British colony had been expecting it.
A rotation can basically double your troop strength for a short time as incoming and outgoing troops are very close.
China could send in troops more suitable--by training and equipment--to crushing protesters.
China could quietly send in more troops than are leaving.
China could reduce the air and naval component in order to have more ground forces under the normal garrison size.
So the rotation is surely routine. But the details of the rotation may not be.
If I was a Hong Konger I would not sleep easily knowing the PLA rotation is "routine." After all, this is pretty routine by now in China's Xinjiang province.
