Diesel therapy is a form of punishment in which prisoners are shackled and then transported for days or weeks. It has been described as "the cruelest aspect of being a federal inmate." It has been alleged that some inmates are deliberately sent to incorrect destinations as an exercise of diesel therapy. Voluntary surrender at the prison where the inmate will serve his time is recommended as a way of avoiding diesel therapy. The case of George V. Hansen involved accusations of diesel therapy, as did the case of Susan McDougal. Diesel therapy is sometimes used on disruptive inmates, including gang members.