We were refunded by Airbnb because we could smell gas and the house had zero smoke detectors or carbon monoxide detectors. You could see a spot where one once existed, but no longer does. This is obviously a safety issue and the main reason why we left.
Secondary, the location is great and easy to check in. But the furniture was so old and not kept up at all. Deep layers of stains and dirt. I felt pretty gross.
I have never had an experience like this via Airbnb.
Very grateful Airbnb was so easy to work with and helped resolve the issue with us.