I was taught to always set the parking brake so tight that the vehicle can’t move even in gear, but not all do that including my daughter. She was driving my 1972 F-250 one day and complained of an odd smell when she arrived at home. Yep, she partially set the brake and didn’t release it when she got back into drive home. That cost me a few bucks. So I guess the warning lights are a good idea. But $100.00?