I agree they'll wait and see, but that could change quickly if there are other democratic protests in the mainland. Beijing is nothing if not paranoid.

Do they execute on the street? I think unlikely. They definitely don't want martyrs. They're very aware that they're more like an occupational force than a legitimate government in HK.

And yes, the West won't respond to any force by China. They could commit mass genocide against the Tibetans and we'd probably do little more than economic sanctions.

But don't overplay China's hand. The fact that they're the world's factory counts for very little. Consumer goods drive economics in peacetime, but count for nothing in war. (Except as potential arms factories for the Chinese). Also, a lot of the Chinese wealth is overseas. If the world froze offshore assets, China's economy could collapse. There is a lot of hiding of money from the government. Especially by government officials. And if the West canceled its debt with China? Don't forget, by owning other nation's debts, China has a vested interest in making sure they succeed. It's a love-hate relationship.