Calendar Events are a very handy way to update all users of issues that impact data. Unfortunately, there is no way in SC15 to push Calendar Events to All users - they need to 'opt-in' to each Calendar Event. And if they don't know they exist, they can't 'opt in'. Admins should be able to set Calendar Events that automatically get pushed to all users, by report suite. Otherwise there is no realistic way to inform my users that something happened that impacted data.