I do this ALL THE TIME. SO many times she wakes early from a nap, or in the morning, and I think "oh, she pooped, so I'd better get in there" and BAM, totally clean diaper!

I stand with my nose in the crack of the door (or even on the floor, with my nose under the door). I can never detect any smells. Boo. I usually end up leaving her, but I feel SO GUILTY when she has in fact pooped and her whimpering turns to all-out crying, and then I change her and she's got a rash from sitting in her poop

You know those stripes on the diaper that turn green when they've peed? They need some sort of smell-o-vision on video monitors that tell you if they've pooped!!!