I'll try and get verification of that technique, the way I've treated heat exhaustion -- I've found a couple of people on the trail over the years in dire need of medical assistance -- was to first get them into some shade --whether constructed or a nearby rock/bush/etc, get something under them (to protect from the hot ground and collect the water run-off -- place a t-shirt under their shoulders and neck area (and then soaked with water) then moderately sprinkle water down their chest and thigh area -- the immediate problem with simply pouring water is one of supply -- water is very precious in the back-country and the need to conserve and use the evaporative aspects of water by fanning the victim (gently) to help cool the person. Excessive heat and cold can have dramatic effects on the human body and both require quick response. In my experience, response-speed trumps location and so it's better to start treatment first rather than move to shade if it's not readily available.

Just an aside, one time skiing solo in northern California I was caught in a 100% white-out and I wasn't properly prepared and experienced profound vertigo and developed classic hypothermia -- I belatedly recognized the symptoms and was able to effect a self-rescue -- but the reason I mention it here was even though it was about 5 degrees F I felt like I was over-heating and my response (which I resisted -- luckily) was to start removing my cap, parka, gloves -- which in those conditions could have been rather serious -- the wind, cold and lack of visual reference short-circuited my brain relatively quickly -- and the same thing can happen in heat exhaustion -- a victim can go from feeling uncomfortable to being "in serious trouble" very quickly.