That one made me laugh out loud when I saw it today. Who is writing these bulletins? Clearly nobody who actually crews an aircraft.

According to the bulletin, you shouldn't request an entire bottle of water, but just a glass. So...in the middle of your flight, when you need another drink of water, you...

a) Go through the entire open-the-flight-deck-door procedure to ask for a glass of water

b) Sit there dehydrated, with obvious safety risks, or...

c) Ignore that bulletin and do what you've always done, take a bottle of water and stow it behind your seat, thereby staying safely hydrated for the entire trip.

Hmmmm....