Just in the last week it has come out that no matter how good a friend you are to china (Cambodia for example) doesn't mean China won't attack you.
Chinese hackers stole data on the Mekong River from Cambodia. You say why would anyone want this data and so what? It is a major river in south east asia, Think Asia's Mississippi, expect it flows threw multiple countries, so controlling the upstream (China's Territories) you can control those countries down stream. Imagine if someone suddenly turned off the Mississippi river before it got to Louisiana? or lowered the flow so it could not be navigable, or raised to flow and flooded all of New Orleans.
Read more at Woods LLP