Baffled

After a conversation I had with a mother at Kindermusic I feel totally baffled by what it means to sleep through the night. We both have babies that wake up every two or so hours to nurse and both co-sleep with our children. She mentioned that her doctor, Dr. Flies (who is pretty famous in Los Angeles, not only because he is Hiedi Fliess' father, he also happens to be admired by many of the la leche league people-not that this means anything) told her that if her baby latched in the middle of the night without opening her eyes and crying then that is considered waking up...Otherwise, our babies are technically sleeping through the night??? Could this be true? Lucy doesn't open her eyes..Just whimpers and opens her mouth and then we fall back asleep. Does this mean that it's just me who isn't sleeping through the night?