The PLA likely sent warships, warplanes, used radar installations and satellites to track the US warship’s movements in the Taiwan Straits, and the US vessel would be stopped if it crossed the red line, exactly what the Americans are expecting to happen with their provocation.
The Chinese mainland must be fully prepared for the worst. We surely do not want a war now. But we should be the one that is least afraid of the situation spiraling out of control as we are defending the territorial integrity.