The fine is intended to curb the poor behavior. If they can’t (or won’t) pay then it seems reasonable to proceed to a different punishment to curb that behavior

The fine is intended to curb the poor behavior. If they can’t (or won’t) pay then it seems reasonable to proceed to a different punishment to curb that behavior. I’m all for pegging fines to income to reduce the likelyhood that fines cause serious harm to violators, beyond the desired effect. But at some point it may not be possible to do anything but take a license.