The fine isn't to punish you so much as to dissuade you from parking illegally. It's to steer you in the right direction. You won't lose your job, you won't lose your self esteem or right to travel, you'll just look for the sign next time.

Giving an addict a criminal record and stuffing him in jail with violent criminals isn't going to steer him in the right direction at all. Rehab might. Plus, it's cheaper than jail anyways!