I have used bags of ice lots of times and it works like a charm. Quick, easy and never had an infection. Don't forget ice is cold so bacteria is inhibited, wort is hot so bacteria is inhibited, hops in wort inhibit bacteria. Pitch health yeast and given those odds they will win every time.
I live in AZ and have had great success with a swamp cooler. Frozen 2 liter bottles work great for the first couple of days I use two in the morning and two at night. Water stays cold and the beer turns out great.
Just tasted my "wheat saison" made with 3724 and it has some cool flavors and nice carb after a week in the bottle. Key to fermentation was the hot AZ temps. Left my bucket in the garage and it was hitting 95 consistently outside. Three weeks and racked at 1.007.