I would boycott the place.
This is a shakedown threat to the public.
I would too.
The number one concern most people have when going into a restaurant is the fear of someone spitting (or worse) in their food.
Since this restaurant's staff have proven themselves to be vindictive a-holes, I wouldn't eat there.
If they're willing to try to ruin a man's reputation, I figure they're willing to spit in my food.