Most of the exploitation is aimed at the families of the incarcerated - you already control the prisoners wages and pay them slave wages so you can extract but

Most of the exploitation is aimed at the families of the incarcerated - you already control the prisoners wages and pay them slave wages so you can extract but so much. But the families? If you move the prisoner far enough away you can bet they won't have the means to make visits, and you can charge families exorbitant rates for your captive market.