I often have back-to-back meetings with different people in my personal meeting room. It would be nice if I could lock out new people from joining the room until I say it's okay. This way people in my upcoming meeting don't just jump into my current meeting (and possibly hear something they aren't supposed to hear). A person joining the room would be told that a meeting is already in progress and to please wait. In a physical space, someone seeing a closed door wouldn't just barge in. They would knock or wait. A BlueJeans equivalent would be great.