It sounds very progressive for a society to admit high income spendthrifts are immune to self reflective remorse, but I feel like we should still try impose penalties to give them an opportunity for growth.
While this theoretically allows the rich to drive said $500 car in order to minimize their liability in the event of a fine, it also means the rich have to drive a $500 car if that is what they are trying to optimize for, which is a decent social tradeoff.
Though it hurts poor people who prioritize their car over other essentials.