The first thought that crossed my mind upon reading the topic's headline was "a possible insurance scam". However it seems unlikely and certainly I would not bring into question the honesty and integrity of this resident. The people involved would have been wiser to keep this to themselves reported the incident to the restaurant owner/manager, other responsible parties ,inspection agencies, etc and place the restaurant on notice in writing of the events, the conversation that took place upon reporting it, along with the parties present, the restaurant's responses and their reaction to this discovery
You can bet , and the customer/resident should understand that the restaurant, its insurer, the state inspection agencies , etc have to consider every possible explanation and they would be remiss not to do so because this restaurant's future is depended upon it.
You can bet this investigation will go back to where that lettuce etc was grown, picked, packaged, distributed, all the way to the waitress placing that plate on the table.
Truthfully I never want to eat in another restaurant again nor have a salad. In my case ignorance would have been bliss