For my sins i provide a VPN service to selected expats.
So someone connects in to the Raspberry Pi then connects out again with our IP address.
Useful if your bank or building society is an arsehole about accepting connections from abroad.
So the user of our IP address could be anywhere in the world.
This makes me think that if you want to stay stealthed you connect to a VPN, then link through another VPN, and then connect to your target.
As for retyping IP addresses that should be like raw meat to a defence lawyer.