In a perfect world I would consider it, although very cautious, yet even then, they should be payed as any other employee, else, companies who would use 'unwilling' employees would net a significant advantage in the market because of cheaper workers.

This could also make the supply-demand system crash, making workers cheaper everywhere because of an artificial supply influx

And of course, in our real, imperfect world, it means that we will have a sudden high in the ratio of people going to prison, as it has already happened in states where the prisons are private so owners 'lobby' cops and judges into imprisoning more people so privates can keep their prisons and pockets full.

Even worse, since a sudden drop in crime or all prisons deciding to strike could lead to an economical disaster, prisons and prison owners will have the upper hand in politics and state.