I've heard this one a few times and even Gordon Ramsay uttered this on one of his shows- that you shouldn't refrigerate food until it's cooled off because it'll create pockets of heat which will grow bateria, etc. I think it's bogus because the entire food (or other) object should cool more rapidly (in it's entirety) in a cooler environment but maybe there's something going on with the surface cooling and contracting? I dunno but if you guys have a FLIR camera it would be easy to check. Thanks!

It'll heat up other food near it in the refrigerator.

Experiment: take a gallon of hot water, and put it next to your milk container. Your milk will sour off within a day.