I thought about it so much when my youngest was that age. He would get up in the middle of the night and raid the fridge and freezer (they had locks on them, but that only stalled him for a week) and he would play with toys. We didn't always hear him. We had one of those alarms that go off when they leave the bed but he destroyed it. He was such a handle, it was so hard. We couldn't do anything major as we were renting, but I always hesitated locking him in and thankfully he stopped with his midnight roaming sessions.