Not that such incidents have not happened before in the 'Cold War', indeed the super-powers had an agreement to prevent such incidents. IIRC there is no such Sino-US agreement, although there is a military-to-military "hot-line".

The guided missile cruiser USS Cowpens...was confronted by Chinese warships in the South China Sea near Beijing’s new aircraft carrier Liaoning....

“On December 5th, while lawfully operating in international waters in the South China Sea, USS Cowpens and a PLA Navy vessel had an encounter that required maneuvering to avoid a collision,” a Navy official said.
Link:http://freebeacon.com/chinese-naval-...tional-waters/