Me too same info was given by the SA. He said usually if our car tint of front windscreen still visible can see the person inside, the police will not ask us go jpj to test during roadblock. But I thought during roadblock they can use the device to immediately test and know the vlt already.  I am deciding vlt 70 for jpj compliant or 40 for more cooling at my front windscreen.  Any experiences to share ?