UNCLOS lacks authority to decide on sovereignty disputes over land features such as islands and rocks. The law applies only in cases of disputes arising from maritime jurisdiction.
So if anyone tries to tell you this treaty will help restrain Chinese aggressiveness in the South China Sea, forget about it. Even if you strip out all the purely sea aspects, there are still lots of disputes over land features that could start wars. LOST has no role in resolving that aspect.
And given all the Chinese actors who could open fire, we have reason to worry about those disputes escalating.