Ever since I started flying in the pacific northwest, I've become a carb-heat fanatic, especially in the big ol' Continental that's turning the prop in the 172 I rent most often. I hit that carb heat every time I pull the throttle back below 2200, and I expect I'll continue to do that wherever I'm flying just as a good habit. Even if he iced up in flight, it's a shame the instructor didn't employ carb heat in the narrow window in the first few seconds where (according to my CFIs) it'll work.
We had an FAA guy ("I'm from the FAA, and I'm here to help!") at our EAA meeting last night, and he talked about how how he's seen a lot of engine failures (usually starvation) where the pilot forgets how to fly once that prop stops spinning and ends up stalling or doing something dumb.