More likely, though still improbable, is that this occurrs in homes that are heated through warm air being piped under the floors (Ondol Heating, "warm air"). A fan may stir carbon-monoxide, which being heavier would normally flow down and lay under the raised floor, up into the breathing areas closer to the surface of the floor. Many Koreans still sleep close to the floor on padded mattresses and they may be breathing in carbon monoxide seeping up from the cracks in the flooring.
Not surprising. About a month ago the system that processed credit cards went down in our store for a few hours. The 'debit' function worked just fine but for some reason credit would not work. During that period it seemed that only a few customers out of many were able to pay cash from an ATM or use debit for their purchases. If they could not utilize credit, they opted not to pay at all and come back later.
"Groups of 'amazingly stupid people who barely have enough IQ to breathe' have traveled to the gas station after word spread of the unexplained event."
Fixed it.