Gas range in kitchen without venting???

I got a call today from a buyer of a home that is buying a home with a remodeled kitchen with a gas range and no venting to the outside. The sellers are insisting that a ductless range hood would be fine.

Here is a warning for one:
1. For indoor use only
2. For general ventilating use only. Do not use to exhaust hazardous or explosive materials and vapors


4. Sufficient air is needed for proper combustion and exhausting of gases through the flue (chimney) of fuel burning equipment to prevent backdrafting. Follow the heating equipment manufacturer’s guideline and safety standards such as those published by the National Fire Protection Association (NFPA), and the American Society for Heating, Refrigeration and Air Conditioning Engineers (ASHRAE), and the local code authorities.

Just so people know, natural gas is explosive. Anytime you have a natural gas appliance there is a worry about gas leaks and carbon monoxide poisoning. People die when they lose power and a BBQ or camp stove is brought into the home for cooking and heating.

New York Times on venting

Looking at this, I'm getting confusing information on it.

 

The weird thing is that I lived in a home with a bad heat exchanger on my furnace. I was getting headaches and didn't know why. When I figured it out, I replaced the furnace and I felt much better. So to read that some places don't care if you're venting a gas range? Seems a little crazy.