Heathrow Airport Security

I've just returned from yet another trip overseas, and want to see if I properly understand the new security policies in London's Heathrow Airport. You are only allowed to take one carry-on and one personal item through security. That's standard pretty much everywhere. However, even though a laptop counts as a personal item, they count the laptop carrying case as a carry-on bag. What's more, seemingly recognizing the absurdity of this position, they say you can formally comply with regulations at the checkpoint by putting your laptop case into your carry-on and then take it out again once you're through the metal detector, and you can do this even right in front of the person overseeing the end of the conveyor belt despite the signs about how only one bag is allowed.

Did I miss anything?