Or they had some sponsorship from somewhere...
Everyone's quoting the pinch of salt. Does it actually do anything? On a long ride we tend to go out with two bottles of water and two of very dilute cordial (lemon and ginger is a good one) between the two of us. I usually drink about two-thirds of what we've got, and Mrs W has about half the rest. I suspect if I put salt in the cordial she wouldn't touch it!
I suppose we do tend to have salty snacks - toasted corn or Japanese rice crackers - which might serve the same purpose.