I have always thought that if it is not your patient's chart, you cannot legally be in it, unless you are rendering some type of care ie. passing a med to help another nurse catch up, starting an IV, etc.
At previous institutions, particularly a very prestigious one that I worked at, audits were run. If your name popped up as accessing an electronic chart, and you did not have a clear role, there would be an inquiry of why you were there, and you would be terminated for just nosing around.
a few of my coworkers are completely paranoid, and very concerned with what the other nurses write in their notes. I have a feeling that they use them as a reference in case their own notes are called into question. A couple of them go through every patient's chart and see what we are saying in our PIE notes. Last night, I held a med due to patient request, and documented the reason why in my note and another nurse brought it up and why what I did was wrong. What I really want to say is get the hell out of my chart, what I do or do not do is between me and the patient and the physician.
My nurse manager knows that this goes on, as one of them prints out the notes to tattle every morning.