Would be great if an inactive Discover user gets a warning after 10-15min of inactivity and if not confirming this warning throw the user out after additional 5min.
If an user keeps D2 open while being ooo he/she will block this license.
If an inactive user gets kicked out after x minutes an admin does not need much control. It would be nice for admins to see the list of active and queued users, but even the kick-out feature for admins is then not really needed. If you see the name, you can call/email him if you need a slot. If he's inactive he'll get logged out after x min.