This is a great example of one of the concepts that I feel isn't clearly understood by some backpackers (of all styles.) Will your skill and equipment allow you to tolerate the unplanned or the unexpected?
I feel that so much time and mental energy are spent preparing for the *planned* trip, which is of course part of the joy of backpacking. Walking distance "A" each day, experiencing conditions "B", cooking at point "C", camping at time "D" at point "E". You prepare and equip yourself for the planned itinerary and then you go out and execute the plan.
But part of the reality (and thrill for some) of being in a remote area and days from civilization is that if any problem arises, it will only be solved if it is solved by you using your skills and your resources.
Things can and do come up: human error, animal encounters, bad luck, and especially weather can and do change your plans for you. Solving these problems is usually just a case of knowledge and strategy, but in some cases there can be pieces of equipment that are indispensable to a successful outcome. Even if you believe in the slogan "bandaid or helicopter", remember that Helos aren't much good to you unless it is daytime and the weather is decent. If it's afternoon, or the weather has socked in, you could be left to your own devices.
Some of the gear lists I see posted here and elsewhere (from heavyweight to SUL) seem not to be tolerant of some basic wilderness "surprises". Anyone who's weathered an August snowstorm in the high country knows that having some calories, fuel, and insulation in excess of the minimum expected need can literally get you through the night.
Losing packs, losing food, falling in a river, illness, cuts, sprains, and as Ryan unfortunately found out, a single bad foot placement can all change your plans. If your selected load is only suitable if *everything* goes *only* *exactly* according to plan, you are rolling the dice.
Granted, how much you are "rolling the dice" depends on where you are and what season it is. In winter, as Skurka pointed out, your margins can be very slim. I wonder if the party in the article understood that based on their equipment, they would die if they couldn't make the hut for any reason? Probably not until it was too late.
Look at your gear list. If you are in a snow storm, will you die? What other situations could you get yourself into and/or out of without assistance?
Keep in mind that I hike in Canada. As I understand it, our trails can be quite a bit more remote on average than what many "lower-48" hikers often experience. We also have (on average) an increased potential for severe weather in more places at more times. (And of course out west we have animals that can be larger and more predatory than you might think.) So take this post with a grain of salt.
Many canucks and Alaskans know what I'm talking about, though...