Here's an eye opening, but perhaps not that surprising, consequence to expanded tourism between China and Taiwan - many mainland visitors go to the island and just... disappear. According to CRI English, roughly ten people have pulled this vanishing act in recent months.
Some of those ten could be checking out just how far they can go before they are noticed missing. That would be useful for the PLA to know. And no, this is not surprising at all:
Imagine several days of such tour groups arriving, sporting short hair cuts and suspiciously almost all male, spreading out across key Taiwanese ports and Taepei? Nine thousand men would be about 20 light infantry battalions. If the PLA stocks warehouses on Taiwan with weapons and equipment, the first wave suddenly materializes. If they can hold the ports long enough, other hidden invaders could land quickly.
So just what could China do with a first wave on the ground before the first Taiwanese orders to resist a Chinese attack are even given?
The Taiwanese better keep track of those tourists, or one day they will be the pre-H Hour infiltration of special forces types.
Remember, it isn't just accurate missiles that can knock out key targets on the island before the invasion officially kicks off.