Sometimes it's used by the state itself for cost savings, as in California under then-attorney general Kamala Harris (now Vice President):

> “Extending 2-for-1 credits to all minimum custody inmates at this time would severely impact fire camp participation — a dangerous outcome while California is in the middle of a difficult fire season and severe drought,” lawyers from Harris’s office wrote in a filing.

https://www.washingtonexaminer.com/politics/kamala-harris-of...