Under what pretense?
Have you any idea how many ships the Chinese would have to assemble for such an invasion?
D-Day in 1944 assembled just short of 7,000 ships, including landing ships. And that was just to cross the English channel!
China would probably have to assemble a similar number, as even though the ships are much larger today, and would have greater holds to carry all the necessary war materiel, they wouldn’t have a ready source of re-supply just 100 miles away (it was about 100 miles from the English coast to Normandy). Thus, they’d have to carry pretty much everything they’d need for a long campaign. And they are not going to achieve air superiority.
We’d know all about their intentions before they ever weighed anchor. It would be obvious it was an invasion force. Once the armada got into the Philippine Sea it would be obvious the target would be either the US or, if it turned south, Australia. In any event it would be war, and the initial engagements would take place in the Philippine Sea, no matter what the target was.