During the lifecycle of a project, people can be added that in fact should not have access to all documents. It's also possible that highly sensible information is shared, maybe even unknown to some of the participants.
In my opinion (and in my current project), I'm adding documents with info known only to some of the managers, with decisions still to be approved by the direction. I can not hide it from greedy eyes.... alas!
I would suggest to add an option to show some documents only to some people, and to completely hide it for others (thus no "you can not read this", it's just not there).