First of all, this has nothing to do with Everett interpretation, and failures of LHC are evidence of its successful start causing end of the world in the same sense as a coin toss resulting in "heads" is evidence that "tails" would kill you. (If you toss a coin a million times while thoroughly investigating and preventing any cause of significant bias, and it always comes up "heads", this starts looking like a compelling argument to stop tossing the coin; maybe "tails" triggers a gun.)
Privileging of a hypothesis means assigning it a probability that is too high. The post was actually responding to people who were privileging that hypothesis after just one failure, and it considered the quantitative nature of such probability judgments: is there a number of failures such that it constitutes sufficient evidence for this hypothesis to become plausible? How many failures are too many? At the point where you do have enough evidence, the hypothesis is no longer unfairly privileged, it's pushed up by the strength of evidence, distinguished from alternative explanations.
The anthropic effect can be distinguished from too-complicated-machinery or sabotage reasons when people have worked sufficiently on resolving the technical and securilty difficulties. Suppose people were trying to make LHC and similar machines work for 1000 years and never succeeded, all the while having a very clear theoretical understanding of how it works, and maybe succeeding in running certain experiments, but with the machinery always failing if they decided to run certain other kind of experiments? This would be the kind of miracle where "complex machinery" no longer works as a feasible explanation, while anthropic principle seems to fit.
We didn't observe an impossible number of LHC failures, so the hypothesis didn't become more probable, but the general idea (which has nothing to do with LHC) is interesting.
I'm not sure why you expect to see LHC failures in the past instead of e.g. either a failure to attain sufficient level of technological development to build LHC, or a vacuum fluctuation preventing destruction of the world. If you wish, a fluctuation which looks just like Higgs.
It'd be trivial to reformulate laws of physics so that anyone who doesn't observe some interaction dies of vacuum decay.
edit: Also, if you adjust probability of theories based on improbability of your existence given a theory, using Bayes theorem, this anthropic consideration cancels out.
Today's post, How Many LHC Failures Is Too Many? was originally published on 20 September 2008. A summary (taken from the LW wiki):
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