Extrapolating from what OPI is saying, I would guess they mean is something along the lines of being unable to check for secondary proxy indicators of care and

Extrapolating from what OPI is saying, I would guess they mean is something along the lines of being unable to check for secondary proxy indicators of care and quality prior to choosing to order food at all, such as cleanliness of restrooms, the number of critters buzzing/crawling around in the dining area, the quality and cleanliness of tableware, the taste of the water etc. the overall customer facing aspects of a normal restaurant which allow you to get a general sense of how the places you cannot see are run. While not a completely reliable or quantifiable metric, the dining experience conveys information that is absent entirely with a ghost kitchen. Ghost kitchens are essentially the opposite of an open kitchen dining establishment. Everything about the preparation of substances you're going to put into your own body is hidden from view, and because this is inherent to the model it's not even something that can be criticized or measured. And unlike restaurants with a public facing facility, there is a much greater likelihood that a ghost kitchen that poisons its customers vanishes and reappears under a different name in the very same location. This would be extremely difficult for a regular restaurant, or even a fast food drive-thru, to pull off without strident public blowback at the place of business. If you agree to eat food from such establishments, there's an implicit acceptance of this blindness to conditions in which the food is prepared. Given the inevitable race to the bottom economics of any food service industry I can understand why this would be a non-starter for a lot of people. Even if you trust people to do the 100% right thing structural forces favor the ones doing the 99% version of it, and then the ones doing 99% of that, ad terminum, ad (literal) nauseam.