Equality Before the Law:

Critics argue that income-based fines violate the principle of equality before the law, as it suggests that wealthier individuals should be punished more severely than others, according to chsprospector.com.
Potential for Undue Hardship:
Individuals with fluctuating incomes or debts might find it difficult to pay even income-based fines, potentially leading to further financial hardship or legal consequences, according to the Centre for Justice Innovation.
Complexity of Implementation:
Some argue that implementing a comprehensive income-based fine system could be administratively complex and resource-intensive, according to chsprospector.com.
Potential for Misrepresentation of Income:
Concerns exist that individuals might inaccurately report their income to avoid paying higher fines, although studies suggest that this is less likely than overreporting, according to the Fines and Fees Justice Center.