I went to school at Naropa University, where a lot of meditation was part of the required curriculum (at least, when I was there; I have no idea what it's like now). I never experience the awake/asleep thing in connection with meditation, either at Naropa or in meditation practice outside the school, but I doubt that I could be in any way considered an advanced meditator.
Should be clear: not every advanced meditator experiences this and is not a prerequisite to be “advanced”. It would just not be unusual if it did happen.
