If we were in China's shoes we would be moving to make sure we had unrestricted access to the resources available in the South China Sea. Simply reacting to what any nation would want as a zone of control by upping the military ante is only going to exacerbate tensions that global economic competitions have already made far too sensitive. And the fact that there are other nations involved as well, nations that have understandable historic reasons to mistrust China, and who, as such, are ripe for us to use against China, will serve mostly to further China as seeing itself being cornered by external enemies, thus provoking them to further intransigence, and open hostility.
A thoughtful nation, in a position to influence events, would see this as an opportunity to play a tensions easing role, rather than a threatening one. And it would use the full extent of its enormous creativity to not only redefine the situation so that, despite what may be there resource wise, it could give up any claim to those resources as a bargaining chip to create an equitable economic sharing zone for the affected nations in the immediate area, as well as simple freedom of traverse for the rest of the world.
This thoughtful nation would do this by initiating multiple, coordinated measures, to give it other options to the resources being given up there, and it would also use those initiatives as an opportunity to build bridges of cooperation between China, itself, and the other nations in the area. It would do this because, no matter what the particular resource in question is, there are usually alternatives outright, or alternative locations to acquire them; alternatives that would be far more productive in the long term than inevitable conflict, and the buildup that would precede it.
The U.S. Navy must get ready for big new Chinese ships that will try to ram Americans who approach their fake islands.