Liability shields would help. Not sure they would solve the public reputation problem? (I've seen the public reputation problem take down restaurants even when the restaurant did not poison the claimant.) But they would give restaurant owners confidence that there would be, at least, no legal liability.

On the balance of probabilities, I'd bet that many people will just eschew dine-in experiences. At least for a year or two. Can you survive the year or two with decreased dine-in traffic? That's the question owners should be trying to answer. If your footprint is small enough, I'd suspect the answer is yes. If you've got a larger footprint than is prudent in the new reality, you'll likely need to make some changes.