I'm currently driving a courtesy car. It's a Nissan. It makes noises at me if it thinks I'm swerving into another lane, which is generally such a shock that I nearly have an accident trying to see what I've done wrong to generate the noise. This happens when I am legitimately changing lanes when motorways merge ... It also has a flashing light in my wing mirror if it detects something in my blind spot. I have, thank heavens, found a way to switch them both off as they're far more trouble than they're worth.
I am looking forward to getting my own car back as soon as possible.