It's not a-priori obvious that this is true. You could adapt the author's style to that case (maybe each vertical column would have a post-lunch grey zone) and then argue the pros/cons.
Even if it turns out this method doesn't work for restaurants, it would still work for stores, offices, libraries, etc.
Even if it turns out this method doesn't work for restaurants, it would still work for stores, offices, libraries, etc.