No police report at the scene, they don't have a foot to stand on in court. She shouldn't have given them sh!t until the police was called.
But then again, if the police were called, she might have had to pay medical bills/pain and suffering. In other words, if she didn't give the old lady her information, then she would have called the cops and would have probably had to go to court or pay, or whatever. Also, let's say that in an unfortunate turn of events, this goes to court, and the old lady sues you for punitive damages. All you say is, "Quite a few of my friends have spare keys to my car, including my parents. I wasn't driving my car that day, and it's possible that someone else was." The old lady then describes you and what you were wearing that day when she is asked to describe the driver of the car (as if she can even remember). "Your honor, let it be known that even if she hadn't seen me before today, which she hasn't, she could still give an accurate description of my physical attributes because I am present in the courtroom today."
Anyways, she pretty much had three options at the scene of the accident:
1. Call the cops and get a report, and maybe wind up paying out of her ass, whether it be higher insurance premiums or whatever.
2. Give the old lady her information with no cops present, like she already did. The old lady is the one who should have called the cops in the first place. Since she didn't, fuck her. Now you won't have to pay for shit. (best scenario)
3. Flee the scene and face felony charges. (not good at all)
Now this wouldn't be true for all accidents, but since there was no damage, don't do a goddamn thing. As far as you are concerned, YOU NEVER GOT IN AN ACCIDENT. How do they have proof that you did, no cops were called? Because they have your information? "Well I lost my insurance card a while ago, someone must have found it and is trying to take advantage of me."
As far as I'm concerned, the old lady probably shouldn't be driving in the first place. I hate old people, and if I ever get old then I accidentally lived too long.