When I was in the state hospital they used it all the time to maximum time. Once the doctor said I was walking angrily( but not talking or acting out in any way) so they surrounded me and tied me down to the mat. Because that was traumatizing I would dissociate and not respond to anything so they would leave me tied down and in suclusion for 23 hours, then by law they had to release me. Because I was dissociating they would then ( I'm told) lead me to me room and put me on the bed. Where I would later find out a whole day had passed.