While I agree with this description of the value of information, I disagree with your interpretation of it in this context. Consider the following, rather extreme example: nuclear power stations are equipped with countless diagnostic systems with several levels of fallback. In a well-built and well-operated nuclear power station these systems will never signal failure during normal operation. This clearly doesn't mean that the output of these systems carries little value. Surely, a test that is always passing doesn't necessarily has no benefit, you also have to consider what it would mean if it suddenly stopped passing.