well it would be better safe than sorry.

the last time China invaded a country (Tibet/India/etc. ) nobody tried to intervene and it happened too fast for any real intervention to be possible.

also the nationalism seem by China now is similar to the nationalism that Germany had at the start of WW2 where they started a policy of claiming land and territory based on medieval borders that none can confirm.

it both cases this same kind of nationalism led to wars despite how short/long or small/huge these wars were.