My government just did the right thing.
So in the legal opinion of all the world minus China it is theft. In the legal opinion of China it is not.
Unfortunately this subtly can not be expressed in a 140 char tweet so the situation deteriorates weekly.
(EDIT: beautiful details by jwtadvice here ) https://news.ycombinator.com/item?id=13195427
Essentially all naval powers engage in some form of this, within the limits of their capabilities.