My neighbors had a baby in September. They are a young couple and I saw the baby when I took over a small gift bag for him/them. I haven't seen that baby since. I've stayed in a lot and of course, it is winter now, but they both work and I find it odd that I see them, separately, getting in or out of the car and so forth, but I have never seen that baby since he was about 3-4 days old. Would you be worried?