I wonder how many night-time burglaries you could get away with using the following simple strategy:
Wait until you think everyone's asleep, then as you creep round the house keep a glass of water to hand. If no-one wakes up then fine, but if they do just mumble 'It's all right, it's only me. I was just getting a drink.' Betcha at least half the time you could make good your escape before the half-asleep victim cottons on!