Gwai Lo Dan
3rd Black Belt
Some folks actually do. I have a step-sister-in-law who has a medical condition ....
True, it's possible.
At the time I saw the woman with water in church, I had started to go to a running store's evening workouts. I was surprised by 3 things:
1) that they pushed longer distances over speed. So if you could do 5 km, then you should try 10 km, rather than doing 5 km faster;
2) that their "running" was jogging with walking breaks every 5 minutes;
3) that most people jogging/walking 5 km had the bottles of water at their waist.
So I had been exposed to seeing people thinking that they need water when in fact they don't (barring a medical condition).