I don't know the right answer, but this sets up some perverse incentives - police might be urged to be "more careful" around rich people than poor people, since

I don't know the right answer, but this sets up some perverse incentives - police might be urged to be "more careful" around rich people than poor people, since wrongly arresting rich people has more penalty. Conversely if you set a fixed dollar amount, then you incentivize poorer people to provoke a false arrest in hopes of getting a payday (similar to common insurance scams seen today.)