a few years back my car insurance company offered me a discount if i stuck a dongle in my car that would tell them how i drive (specifically reporting hard accelerations and stops), with a base discount of 10% even if i drive like a madman up to 40%ish if i drive like a grandma. and of course naturally my first thought was "huh i bet i could make something running off an Arduino that filters hard brakes and accelerations out of the incoming data stream to get that 40% discount" and i got as far as looking up OBD2 protocols before realizing that that would just be insurance fraud. yes im an engineer raised by two engineers how could you tell