But if your "sting" is, let's say, a percent of your 100,000 salary, yeah that's going to not be fun but to get your car back, you'll do it and learn your lesson.

If it's a percent of your $30g salary and you're living paycheck to paycheck while trying to feed 3 kids, the effect is going to be substantially worse. I'm not saying we can just waive penalty fees situationally but the inequality is definitely going to be there regardless.