The vast majority of these exams are done under the authority of a search warrant issued by a valid court. The police have the authority to access the data on the device...their method of doing it is not really relevant. One of the reasons that companies like Cellebrite of Greyshift are so secretive with their exploits is because as soon as Apple or Google get a grasp of how they are bypassing security mechanisms, they push an update to block it. It's a constant cat and mouse game.