I don't know if a third-party app might be able to duplicate this functionality, but even if so the problem is third party apps can be banned, and can be seen o

I don't know if a third-party app might be able to duplicate this functionality, but even if so the problem is third party apps can be banned, and can be seen on phones by authorities and used as a reason for suspicion. People have to be bold enough to install it to receive messages too.