Are we all so tired from sitting on the train, bus, or aircraft, that we cannot raise ourselves and carry our own bags up the stairs or over to the lift? In my opinion, the LGW rules are correct and admirable, and should be followed obediently.
Or are we all so tired from the aforementioned train/bus/aircraft that we cannot stop ourselves stepping on to the escalator behind someone who we fear might drop something on us? Just a thought.