So long as you never go to same restaurant twice, I guess you will be okay. They do tend to have long memory for bad toppers so I would never return to one if I did that.
You’re right. I would not either. But you also have to realize that the compensation system would have been drastically changed, and to keep clientele, owners would have to be on the watch for behavior like this from their employees. Frankly, if I even suspected that a staff member spit in my food I would start the evidentiary accountability process right there, have it tested and I’d sue the ass off that place.