I create some boards and share them with my students so they could view-only. I think it would be good to have the ability to turn off visibility of showing who is on the board. Students may prefer to view the board without being seen that they are on the board. I think it should be the feature that the board creator indicates whether it shows who is on the board or not.
Even as a board creator sometimes I want to view a shared board but do not want others to see that I am on the board. However, right now when I am on the board it will show my account presence.