I would peacefully disagree with your comment on Cold weather not causing dehydration as quickly. I may be parsing your words or thoughts, but coldness is a false sense of hydration security.

Perhaps because people don't stay out in the elements as long in cold or the activities are not as vigorous but people get dehydrated at alarming rates because of this false sense. A cold wind will absolutely dehydrate a person.

As to to the drink on demand in the military. i remember those times very well. A deep booming voice saying loudly, "HYDRATE".

I use that with my son to this day.