On the domestic leg of a trans-pacific QF flight a few years ago, about 10 of us boarded in SYD to go to BNE, about 1 hr flight time. All the LAX pax were zombies, so the FA blew the whistle - hard - as the recorded voice droned "... a light, and a whistle PHWEEEET for attracting attention...". Did they wake up! Funniest thing I'd seen in years.