Yeah I always have.. I think its important to let them know whats going on, even through they may not fully understand. DS is now 10 months, and even if I know I wont be home when he wakes up I make sure I tell him before he goes to sleep where I will be and who will be there when he wakes.. If I am home I always tell him that I will just be in the lounge / kitchen and right here he if needs me. It might sound silly but I would feel worse if I just disappeared.. I mean if someone did that to me now even as an adult I would find it rude iykwim...