As much as it pains me to admin my shortcomings, I've driven my kids all the way to school in the morning before and didn't notice the conniving little farts were still in their pajamas until they got out of the car.
I don't know if everyone makes these sort of foolish and sloppy mistakes, but if you get up late and it's a mad rush to load up and get out of the garage, things happen. When you are picking them up in the car line after school, it can be daunting... you are paranoid about running over a kid, there are crossing guards yelling at people and the traffic is gnarly. I can see myself being so distracted with everything else that I would actually be so dense as to forget to check and see if I have the right kids before I drove off.
I could admit to a lot more embarrassing stuff, but I think that's enough to cover it for now... plus my wife might read this
My sons go to school quiet often in their pajamas. Of course, the classroom is our dining room. :O)