What places can legally use mobile jammers?

For now, prisons in many countries allow the use of jammers. The aim is to prevent criminals from contacting the outside world and committing crimes. France currently allows cell phone jammer to be used in cinemas. To ensure that audiences can enjoy movies and plays without disturbing them. Some European countries allow the use of gsm jammer in public places such as restaurants and concerts. To ensure proper etiquette. China, Japan and some Asian countries allow education agencies to use blockers. Prevent distractions and cheating in classoom. There are also many countries that use drone jammers to keep large exhibitions and venues in order.