I think there are two points here:
1️⃣ Investment is free, but it's an unprotected market; you bear the risk yourself!
2️⃣ This is an individual case, and a civil lawsuit at that. Such matters can range from minor to major, but the room for manipulation is enormous.
In fact, consider this: if Zhang profited from this, or if Zhang invited more than just Liu, turning it into a group incident, then this outcome would likely be very different.
A group incident is egregious; profits are worth pursuing, and many charges could be brought against them, starting with illegal business operations.
In summary, I'm saying two things:
1️⃣ When investing, be vigilant. In China, you're gambling in a market without sovereign credit backing; you bear the risk yourself, and the chances of recovering your losses are slim.
2️⃣ However, if you're thinking of exploiting loopholes to scam others, or if you think China is above the law, don't. This is an individual case, but the procedures vary from place to place. Trust me, don't break the law. Live a law-abiding life and don't have any crooked thoughts. There are many intelligent people in law enforcement agencies, and their efficiency can be quite high when needed.