You are talking about extension springs? In my experiance torsion springs break very harmlessly. They just snap and unwind but stay on the shaft. Torsion springs are the only kind I have myself seen used for garage doors.
Unfortunately, they're also a bit more fragile. Speculation (mine) is that the metallurgy required to make a big torsion spring makes the material more brittle than standard spring steel. Or maybe they're just thinner and cheaper.
They sure are loud when they snap though.
I've never even seen them outside of California.
Sorry, I phrased that poorly.
There are many states where the typical California tilt-up single-piece door with levered extension springs does not meet code.
Apparently they are not secure in very high winds, so they're especially dangerous in hurricane/tornado country.
I think you misread his comment. He wasn't talking about the same kind of spring you are.