収束ゾーンでのライフ: Life in the Convergence Zone

That's a question. The answer, according to the NY Times story, as quoted above, is that the inmates volunteer for the work. Of course, in a prison, the management has a lot of leverage to make an inmate's life miserable if he doesn't "volunteer".

Another question: If the prison system becomes a profit center for the state, what sort of incentives does that place upon the state's administration of the justice system?