Happened to me just 3 weeks ago.
I parked the car in the mall parking lot and was walking back to the car. Another car was pulling into the next spot, no big deal but then I noticed my car shaking a bit. I ran and noticed the pulling guy's front bumper hanging half and it kissed my rear tire area, small dent near the tires, good amount of paint scratched. We didn't call the police as we knew they won't come but his insurance company is giving me so hard time, making me write a newspaper article on what happened (the form is quite extensive and although I gave all information to them over the phone, now they want it in writing. Why the f*** they don't ask it in the beginning then?).
The amount of time this sh** is taking is getting on my nerves.
Seriously, even if they don't come, still call them and make the guy involved in fender bender talk to your insurance company.