asleep or not asleep?

If you ever find yourself on a bus here in Hong Kong you will very likely find yourself seated next to a person who is sleeping, or pretending to sleep. It's a incredible thing really. People can be fully alert walking to their bus stop, interacting with others while awaiting the bus' arrival, but then as soon as they hit the seat in the bus their eyes are closed and their head tilted downwards. The best part is that they know exactly when they need to get off without lifting an eyelid. The awkward part is when the bus makes a wide turn and the person next to you really is asleep, you find yourself leaning way farther than you normally would to avoid being mistaken as a pillow. Sometimes I just want to wave my hand in front of their face to see if they would look up, but after some logical processing through that thought I realized that in the chance that they did open their eyes, it would be difficult to explain why my hand was in front of their face and not seem like a creep. Perhaps they enjoy a little power nap while in transit. Perhaps they are really perceptive and don't need visual cues to get places. Perhaps they are narcoleptic. Perhaps it's just a little game they like to play to pass the time: am I asleep or not asleep?