If they decided to mess with the Chinese, there would not be arm wringing, nor concerns about diplomacy, merely a crushing fist coming down both sides of the border.

Casualties in the thousands would be acceptable for both the Military, the Insurgents and the Locals as far as the Chinese government is concerned. If razing a zone 2 miles deep, using a minefield and shelling anything that moves in the zone, I imagine it would slowly and deliberately be constructed.