I was responding to your comments about how it compares to a legal process. The latter bit has entirely to do with moral arguments.

Perhaps I talk about Law and Ethics in a similar way. You should disregard that because I always talk like that. :D

Here's how I personally think of this type of situation, morally and with regard to trust...

A stranger is writing a letter, but gets distracted and walks away, forgetting they left the letter in the open: it's cruel and morally
indecent to read without their permission. But not a betrayal of trust (they didn't trust you).

A stranger gives you a letter, telling you it contains their correspondence with someone else, and incriminates both of them
in a plot against your community, additionally you are an authority in your community: it's not only fair but required to read it.
The community is trusting you to enforce the rules they've agreed to abide by. Not a betrayal.

A stranger gives you a letter, telling you it contains their correspondence with your personal friend, and incriminates both of them in a plot
against your community: you wouldn't read your friends private correspondence without their permission, and because they are trusting you
not to and you don't think they would do anything terrible (if not why the hell are they your friend?), reading it is a betrayal of trust.

I think Murphy and the Imms are in a situation like the second example, not the third, and the third illustrates my view about "friend like privacy".

edit:I'll admit the third is pretty shoddy/bad, but I'll leave it up because it hopefully it reveals the difference in how we might be using the word trust, for the sake of clarity.
Mine is obviously personal and not some gold standard.

Point being, without writing an essay, this isn't morally black and white and I think it's ridiculous to imply the staff did something abhorrent by reading the skype log.

And yes I agree if they want people to play their game, they should act in a way that coincides with most people's definition of trust.
However my impression is that people who disagree with my assessment of situations like number 2 are largely in the minority.