As an added note to all this, the annual Philippine/US military exercise kicks off tomorrow off Palawan, about 500 km south of Scarborough Shoal.
Some 6,800 troops — 4,500 American and 2,300 Filipinos — are expected to participate in this annual exercise, which includes computer-simulated command post exercises, multiple field training exercises and humanitarian civic assistance projects in pre-selected areas in Palawan...

... The venue of the actual training exercises includes the West Philippine Sea (also South China Sea) off Palawan where both forces will be pursuing amphibious exercises; and gas and oil platform defense and retake.
The Philippines refers to the South China Sea as the West Philippine Sea.

Of course the exercise has been planned and publicly scheduled for months, which raises the possibility (not certainty) that the Scarborough Shoal confrontation was deliberately provoked in time to coincide with the exercise. That raises the question of why the Chinese would want to do that.

While we tend to focus on the messages China may be sending to its neighbors, the US, etc, one possibility (again not certainty) is that the primary target of the messaging is domestic. Could the Chinese government be trying to hold up what they call an effort to push Chinese fishermen out of their traditional fishing grounds while at the same time masses of imperialist running dogs are staging war games in the vicinity as a way to cultivate a perception of threat and persecution, and to promote nationalism and patriotism?

Obviously there are numerous unknowns in that picture, and that may have nothing to do with what's going on... or it might.