The Treasury Dept just indicted several Chinese nationals for running a scam VPN service in the US. The criminal enterprise, the Treasury Department said Tuesday, was a residential VPN proxy service known as 911 S5. Such services provide a bank of IP addresses belonging to everyday home users for customers to route Internet connections through. When accessing a website or other Internet service, the connection appears to originate with the home user.
Basically, you think you're getting a VPN service but you're actually just providing computer resources for their illegal networking operation.
US sanctions operators of “free VPN” that routed crime traffic through user PCs | Ars Technica