If we're sharing security information, and that information is provided to us under an absolute guarantee of secrecy, we cannot simply divulge that information. The government that provided us with that information has a right, for whatever reason...because we don't know the entire security issues in that particular country. What may look relatively innocuous to us may in fact be damaging and detrimental to not only the government but to the safety and security of its citizens. So we honour that commitment.
Similarly, if we were to send information to another country because we needed to work on the issue of terrorism on a worldwide basis, for example, another government looking at that information might say, “How would this really harm anyone if we released it? Well, we don't know.” We have the information; they don't.
I would be very reluctant to ever give a government information that could potentially be released and come back to injure our national interests or the safety of our citizens. So I don't know how you even bring an injury test into this kind of a context without having extensive reviews of both countries' security information, which you'd never have access to.