That'll do it, and quick. First you get warm and sleepy, then you die. Sorry about your friends.
We have had a number of carbon monoxide poisonings in my area in the last 20 years. One involving a gasoline generator in a basement. One was a kerosene heater in a van. And the other was a charcoal grill in a small cabin. Dead, dead, and hospitalized.
This kind of thing may increase in the OWS camps as real winter sets in. The city officials who allow these people to camp, in violation of all kinds of laws and public safety rules, are also culpable,
Don't those devices all say not to use indoors or in an enclosed space? Why do people disregard those warnings?