It is not nearly as implausible; China does not have military bases around the US like the US has around China. The US frequently conducts FONOPS into Chinese waters though they typically stay fairly close to the 12nm mark. And like I said, Chinese and US ships don't risk collision with each other. Throughout pretty much all of the FONOPS, Chinese ships shadowed with warnings and never tried to physically block them. Furthermore, it is incredibly hard, if not dangerous to block a ship from entering your waters; it's not like you can park your ship in a gateway and they couldn't get through. It's the open ocean and they can try again and again and when they pull back, it's a non-story but if they get through, it's headline news that China failed.
This has never happened in US or Chinese history. It's a retarded level of imagination on your part, both for how China would act and how the US would act. You're clearly starting to let your emotions run things in your head.
I actually feel it's less than a 50% chance the US would dare fight if we move to take Taiwan but the CCP doesn't gamble with no 50% stakes on the well-being of all Chinese people. I'm fully in agreement that if we go for it right now, we can win. But that's not the plan; the plan is to go for it and win in a future where that victory is bloodless and costless. That's the CCP plan so your "We can probably win now" sentiment is irrelevent and actually falls closer to being goaded into a conflict prematurely.
Nobody would dare shoot and they both know it, not between the US and Chinese forces. That's a decision that could tee off WWIII; no commander would let that happen based on the whim of the moment. The US ship would keep sailing, answer the radio, "We are operating within international laws and will continue to do so," which is their view as they patrol with the ROC, and the Chinese ship wouldn't fire, but it would shadow and continue to warn. This is how things have been done between the countries for decades, not your emotional little boy fantasy of cucking them and them beating them.
That's the point of the patrols; it means the area is under us. There's no such thing as patrols only against other patrol ships. I'm fairly sure that if any ROC government vessel tried, they'd be repelled but civilian ships will be travelling with proper permissions and is normal for business and if not, they they will be boarded, as is what happened with the tourist ship a few days ago.