Years ago I was leaving a small restaurant in Connecticut.
I glanced back to see that the 3 high school guys who took our table had also taken the tip money I left.
I approached them and said very softly, "Look guys, the waitress is working harder than any of you probably will in your lives. So, if you want to be cool, put it back.
One of the guys said to his pal, "I told you not to be an (body part)".
Turns out another, more senior waitress overheard enough to put the events together correctly and proceeded to go at the young bucks at volume 10.
I was already leaving so I just continued on my way.
As far as social media levying justice goes....remember the lady who was caught on a security video putting a cat into the garbage can in England? I think she was fired from her bank position later that day and killed herself within a few days.