Definitely done it too (and still will if someone falls asleep in the car), although as others have said I've done more the drive to nowhere - my kids seemed to sense when I turned the engine off and woke up. Like Cranky Kitten, I've found a few dream houses over the years on my rambles. And you're wrong you know. With two babies you do it even more because both your darlings asleep at the one time is WAAAAAY too good to mess with!