Don’t eat snow to rehydrate yourself. It will only make you freeze to death faster. Melt the snow outside of your body first.
Wait, how does that work? It seems like it should take the same energy to melt it either way.
Also, do people not know every berry isn't edible? Even here where not a lot grows, there's plenty of decorative ones around that will give you the violent shits.
When people say that, they mean they're so much smarter than everyone else they could fix it all in a moment.
Of course, in reality, the cranky old man saying that has just stayed so uninformed about the issues he doesn't know what he doesn't know.