There is actually proof that this works. Using Felony Probation and Parole in a particular state as an example, at one point it went to the department that ran

There is actually proof that this works. Using Felony Probation and Parole in a particular state as an example, at one point it went to the department that ran Probation/Parole. So the Probation/Parole Officers were encouraged to aggressively pursue getting the fees for probation/parole. Then it was changed to go to the states general fund (so the department stopped getting it effectively). MAGICALLY the officers only got encouraged to care about restitution payments and started being very blaise about failure to pay fines and fees.