Unfortunately I missed my flight this morning to JFK. I knew about the charging rules so put my dead laptop in my hold luggage. I got through security fine but when I was in the lounge I was contacted by some staff saying I had to power up the laptop in my suitcase. They said they had to take me off my flight while I waited for my suitcase and had to go out into arrivals. Long story short I charged by laptop and was booked onto the next flight.
However, before I got onto my next flight, I bought a small camera for my brother at duty free. I did not buy any batteries for it. It was spotted when boarding the plane so I was not allowed to take it on as I obviously could not power it up.