You've managed to completely miss my point. If the policy were about making sure that people were paying attention, then they would interrupt people sleeping,

You've managed to completely miss my point. If the policy were about making sure that people were paying attention, then they would interrupt people sleeping, reading dead tree books, wearing earplugs, or doing anything else that takes their attention off of the attendant. They don't. The policy has been retconned into being about attention, but the claim that it's about paying attention is belied by actual behavior.