All 50 states award good-time to prisoners for not rioting, for not beating each other to death, and otherwise for not tearing up our prisons and costing excessive expense.  When a reasonably well behaved prisoner is released, that good-time is theirs, and they hit the streets free and clear, not counting any residual probation time ... except in Alaska and two other states.  Alaska's Mandatory Parole scheme keeps a prisoner released to their earned good-time on a leash that says that they can be returned to prison for any little thing that makes their PO nervous.  Whereas, if they had been vested in their good-time, as 47 other states do, they could be returned to prison only for committing a new crime.  Some Mandatory Parole violations include drinking only one beer, sleeping at a friends house overnight, or attending church without permission (honest, this is true).  By simply vesting prisoners in their earned good-time, we could reduce recidivism, and expense, by a huge amount.