When is it okay to use mobile phone extraction tools? Can they be countered?

Is privacy a right or a privilege? If someone is accused of a crime, does the person automatically lose their privacy or should they be entitled to some? In Argentina, for example, police use these MPE tools often, without any regard to people's privacy. How can I secure my devices so that I can be protected from their methods?

argentina crime mobile mobile phone mpe people phone police privacy privilege tools