"Cold Crashing" in the context I posted may or may not be the correct term. Its just the way I describe my method of getting the wort temp down from boiling to under 70* as fast as possible. Like I said I get it done in under 2 minutes and its done based on some good ideas. You see everyone posting about infections, getting the temp down as fast as possible so you can pitch the yeast and get it under an airlock limits the time that your wort is exposed to the air and anything that might be floating around out there. A lot of guys in here call useing Ice in the wort a gamble, well it might be but its a small one. I talked to a guy at Ready Ice, one of the ice suppliers here and the ice guy at the grocery store chain here. They both use RO to make their ice and are required by law to do a whole battery or testing, so, my ice supply chain is clean. Also you see guys posting about sanitizing ziplock bags and useing that to freeze their own boiled water in, Really? Those zip lock bags come off an assembly line at Very High temps and are molded and closed all in the same high temp environment in seconds, they are completely sterile inside, same thing with the ice bags.
I think that a lot of people have bought into the idea put out there by the water bottling companies that our public water supply is not as safe as it should be. With very few exceptions that is BS. If your on a well or maybe some CO-OP water system then you may need to take some extra steps. I live in Boca Raton, pretty fancy place but their water distribution sucked when I first moved here, boil water orders regularly due to broken water lines. Not so much anymore, but the water is Green if you put it in a white coffee cup. The chlorine boils out very early in the boil process so its never been a problem.
IMHO, and I am not any kind of expert but I have made about 40 batches with only 1 bad one and I have done every one the same way. If you use a wort chiller, it seems you need to take a lot of care to make sure it is sanitised before putting it in your wort and it also takes much longer to chill the wort than ice does. Its also a lot more trouble screwing around with a waterhose and all that. Ice drops the temp and brings up the water level all in one step and in 2 minutes I have condensation on the outside of the pot.
Bottom line is you have to make sure everything is clean and limit the exposure to possible contaminates. IMO ice does that better than a chiller or an ice bath, But, its your beer and you can do whatever you want.
This works well for extract brewing which is all I do. For AG you have to pay pretty close attention to water volume and ice may not work so well.
Sorry for the rant, but this has been my experience with it.
Ice is fine, but using it means you have to take into consideration the dilution (both of SG and IBU) when planning the recipe because you are after all cutting your beer with water post boil. It's easier when you brew extract because you just have to use more extract for less volume, but I know that for me, on my setup, using all grain, it's more straightforward to do a full boil and then mess with wort chillers. Topping off used to throw out of whack my mashing ratio quite a bit, leading to temperature and efficiency issues.
Plus you have the argument that full boils taste best, but I'm not so sure I buy into that one.