It would be like using drones and scanners to stop a million people from crossing the border. It just wouldn't work. You can't hire an IT person in China without them giving all your stuff to the PRC if the PRC is interested in your technology.
Civil lawsuits are always a 3 party process (unlike the two party process we have), and the third party is the PRC. The Court decides what is in the best interest of the plaintif, the defendant, and the state, and plaintiffs with a strong case can lose if their interests are sufficiently subordinate to those of the state.
Keeping companies from doing business would have similar bad economic effects, but I do wonder how you would manage that...like the Cuba embargo? I guess we have Nixon to blame for all of this.