I truly believe something like this really could happen to any parent, if all the wrong stars aligned - so I'm very interested if there are devices on the market now to prevent it somehow (weight sensors) or if legislation could be passed to require such safety features in cars or car seats.
I can't believe, with all the other car seat safety regulations, that stuff like this isn't already required or widely used. And I'm not much of a child safety/child proofing enthusiast (I don't use finger guards for doors or toilet seat locks or anything like that) - but the potential for a mistake like this scares the bejeezus out of me.