Curious on the BA Blurb on "Well Being" that they seem to ignore dehydration.

Is that something that only young people suffer from these days, or are BA seriously missing an on-board wellbeing issue? I mean the exercises are 'cute' in a hahahaha sort of way, but everything else there seems to ignore the topic. Why do they hand out water? Presumably because people want it? Or need it? Or is it a placebo? And then they refuse top-ups?

Does not compute, Captain. Where or what am I missing here?