Another prominent US defense publication, Inside the Pentagon, on 5 June 1997 published an article which indicated that China is considering outfitting merchant ships with ballistic and cruise missiles, and use the protection of surrounding merchant vessels in a possible attack against Taiwan ("Busy Sealanes Could Provide Chinese Cover for Missile Attack on Taiwan", Inside the Pentagon, 5 June 1997).
Speaking at a 22 May 1997 symposium on Chinese security issues at Fort Myers, Virginia, one expert postulated that China could use such an approach, and that such an attack "would be using technology that is currently available or speculated to be available to China in the next three years."
The expert said "it's a scenario that does not require China to have a blue water navy, amphibious landing ships, nor to land troops on Taiwanese soil." He said this so-called "defensive containment" strategy would be based on China's calculation that the U.S. government, fearful of military commitments that may result in large numbers of U.S. casualties, might not come to the aid of Taiwan should it fall under threat of Chinese attack.
China's expected acquisition of Sovremenny-class destroyers with SSN-22 "Sunburn" surface-to-surface cruise missiles, as well as its current inventory of C-801, C-201, C-802 missiles, "could give the Chinese the capability to contain surface action in the Taiwan Strait by placing a reasonable doubt of safe passage to ships attempting to enter the area," said the expert.
He estimated that a couple dozen of these cruise missiles, launched five nautical miles from the Chinese mainland, can hit a target 150 nautical miles away in less than two minutes. By shooting from the shallow waters close into the Chinese coastline, from amid the clutter of merchant vessels, China would be placing United States warships in the position of having to launch a counterattack on vessels located within Chinese territorial waters.
In addition, China could deploy hand-held Global Positioning Systems receivers on merchant ships to assist it in targeting Taiwan, and U.S. ships would be at a loss to pinpoint which Chinese ships were supporting the attack in this way. The Chinese battle group would be surrounded by dozens of merchant vessels, some engaged in commercial shipping, others assisting the battle in targeting, he said.
To defend against such a scenario, the article stated that the United States should make clear its commitment to the defense of Taiwan, undertake joint exercises and work out rules of engagement and command and control.
See War of 1812.
Currently, the threat from merchant ships is but half the trouble; the other being the multitude of river barges plying their way to half the U.S. population.
There are definite problems trying to hit a ship in the clutter of the litoral environment with a remotely launched missle, but that's a technical problem, not a political one. There shouldn't be many third country ships within 5 nm of shore anyway, so at worst you hit the wrong enemy ship, which results in not hitting the dangerous one(s).