I keep seeing this conspiracy get repeated. The conspiracy goes like this: car manufacturers don't want homeless people sleeping in cars, so when a car is off, the air vents automatically close. They say you must crack open a window, but this wouldn't be good in the winter time when it's cold, and you can't leave a car running while parked because of the risk of carbon monoxide poisoning. So, a homeless person in the winter time who only has a car would have no choice but to sleep with the car off and the windows rolled up.
Generally when pressed for evidence, this is the article they like to respond with; https://arstechnica.com/cars/2014/12/new-zealand-couple-manages-to-lock-themselves-in-keyless-car-for-13-hours/
Is a person at risk of suffocation from oxygen deprivation if they sleep in their car with the engine off and the windows rolled up?