Lots of people have died from drinking sea water. It's still a Very Bad Idea. Your argument is along the lines of "They got technical details wrong; salt water

Lots of people have died from drinking sea water. It's still a Very Bad Idea. Your argument is along the lines of "They got technical details wrong; salt water is sometimes important; therefore the whole thing is wrong." But that is like saying the advice to "Do not handle rattlesnakes" doesn't apply because some folks get a great deal out of handling rattlesnakes. The fact is, people who don't know what they're doing shouldn't handle rattlesnakes… or drink sea water. Now let's talk about oral rehydration salts -- the non-fancy name for the salt water and "glucose transporters" you described. The salinity of Oral Rehydration Salts/Solution is nowhere near as high as sea water -- and without the sugar, saltwater doesn't rehydrate. The formula for making it yourself is about 1/2 tsp salt in a liter of water, plus 6 tsp of sugar. That's a lot of sugar to balance out just a little salt: 1:12 ratio. A quick Google suggests that 35g of salt is what one would expect in a liter of sea water (on average). A tsp of salt weighs 5.7 g. Therefore, the concentration of salt in sea water is 6 teaspoons vs 1/2 tsp in ORS, or 12x the concentration of salt. And no sugar. I drink ORS on a regular basis to deal with one of the side effects of chronic fatigue syndrome: an imbalance of hormones in the body which leads to insufficient electrolytes which leads to POTS (postural orthostatic tachycardia syndrome), dizziness, muscle cramps & twitches, brain fog/inability to think straight, and inability to drink adequate water. ORS has been a total life changer for me -- before, doctors just said I was "too out of shape" when sitting up/standing led to a doubled heart rate, dizziness, the feeling that "the bottom dropped out of my head", near fainting, etc. Because that's a valid explanation when a 27-year-old nearly passes out from standing up. (Not.) Drinking a little salty-sugary solution solves my symptoms in 20 minutes. But I sure as hell wouldn't drink sea water.