Probation and parole are suppose to rehabilitate criminals. A major reason for many crimes is alcohol. The prohibition of alcohol while on probation or parole is for the offender to learn how to engage in activities that don't involve alcohol. This is especially vital to criminals who tend to get in trouble as a result of alcohol but are law abiding when sober. Sadly, the restriction of alcohol to those one probation and parole is weakly enforced. A twice daily PBT is easily fooled and offenders of the continue in their self destructive behavior.
Having special IDs that readily and easily indicated to vendors that the customer is not allowed alcohol would encourage the rehabilitation needed for parolees.
Additionaly, it should be illegal to sell to those on probation