Another Kate theory: She's been kidnapped

Just popped into my head and haven't seen it mentioned before. Could she have been kidnapped and there's an ongoing negotiation/hunt for her. Revealing this to the press and public could jeopardise chances of finding her safe and alive. Kids have been taken out of school for protection, the few times Will has been seen he's looked like shit, the other times it's a body double with Kate to keep the facade up in the meantime.

Edit: Her mum (and possibly sister?) participated in the car photo to keep the public and press satisfied just a bit longer while police/special forces negotiated/hunted for her. And the reputational damage incurred with these terrible Photoshop/body double events will be forgiven once we know what had really been going on.

Not completely out there, but fits with all the weird stuff going on and no public appearances.