What Would You Have Done?

This afternoon, I was about my own business...running errands...

It was just in and out of the phone store to get a car charger, in to the grocery store to decide what to cook for dinner, in to the music store to get a guitar pick for Megan, and so forth...all in one shopping center... quick, quick before school got out, or so I thought...
As I got out of my car and headed to the phone store, I heard a commotion between two people. A few cars away from me, out in the open, for all to hear, they were exchanging foul, degrading words.
I tried not to pay attention and entered the phone store.
A few minutes later, I exited the store, phone charger in hand, and they were still at it, now it was LOUD, and it was apparent that this was a Mother and Son in a HUGE, FOUL-MOUTHED, DEGRADING Shouting Match....HAND GESTURES to match the UGLINESS. There were words and accusations exchanged that NO ONE should ever hear in their life time..NO ONE.
It was so bad that I was sure it was "staged" by one of those shows like ABC's 20/20 or Dateline NBC and that any moment, a reporter would approach me and ask what I thought about the scene and why I had not done anything.
Just as I was entertaining that thought, my friend came out of another store and asked me if I knew them. I said no, and she told me that she knew their names and that the husband/father works for the Sheriff's Department so calling 911 was not a good idea. HUH?
At this point a few people had tried to intervene as the Mother called the Son every degrading name imaginable and the son just dished it back. This was Verbal Abuse that I was quite sure would turn to Physical Abuse shortly. Anyone who got near them just got yelled at and told where to go.
So what did I do?
I put myself in the place of the son, then in the place of the mother, then I called 911..and they came...right away.
This scene broke my heart. I could have never gone home without feeling like I did "something".
What would you do?