Personally, I think that the autowalks should be fitted with sensors so that they don't move unless someone approaches it. This has been trialled at the station with some degree of success, although I don't believe it is as energy efficient as switching them off completely. Obviously in the day, all the autowalks should be fully functioning and in an ideal world this wouldn't be a problem. But escalators/autowalks cease on many occasions throughout the day, mainly due to the emergency stop button being nudged or if there's been an accident, it needs to be switched off for health and safety reasons. The Customer Service teams check the travellators, escalators and lifts throughout all three terminals at regular intervals on each shift and restart autowalks etc if necessary, but obviously this is not always going to be number one priority.
I'm not trying to make excuses here or disspell anyones argument, just want to tell it like it is from my background in Customer Services.