Vacation Mode or Invisible Mode
For users that have VCS on their smart phones, and they are installed in Private mode, there is no real way to be "off" the system. You can't logout of the application, it is always running. When you go on vacation, it reports you as available, but off campus. Kind of misleading. Yes, you can set DND, but still misleading. It would be nice if there was some way to change your status/presense manaully. So you could have it say you were On Vacation, or something to that affect (perhaps configurable to what it says). Or at the least have a Invisible Mode, so you are in DND, but appear as Offline for your presense / status.
This is not an issue with the Shared mode installs since you can just click logoff.