FYI, If you use open calendar info, be sure stuff that should be private is marked as such.
Situation: I had a contractor who wasn't working out. He was a six month temp-to-hire. After three months, we had some issues with professionalism. Behaviors were observed, documented, and discussed. For a while things got better, but then slipped again. When I got back from vacation at the end of June I got a couple more reports from my directs and customers of incidents of the same. Last week I made a decision to let him go on Friday July 11. I told my replacement manager and my boss. I also started working with HR to get some replacements. We were very careful about what discussions were made and with whom. We were also very careful about the hardcopy resumes and other notes so the outgoing contractor wouldn't get the news before we I was going to deliver it.
The weakness is that several of us use open (Outlook) calendars. This helps in general communications, but the contractor was setting something up and noticed a few of us had interview invites from HR and figured it out a day early. He approached me and asked "Am I being let go tomorrow?" He was calm, but clearly upset. Upon his request he was let go a day early.
My boss requests that his directs have open calendars. While I can restrict who sees my calendar, it gets a little more tricky who sees what. Outlook has a little checkbox on the bottom right corner labeled "Private" which will hide the details from others. I recommended to HR that we start using this in replacement (or other sensitive) situations. We'll see what happens. This could have been a lot worse considering the contractor also had some elevated IT Admin access. Fortunately nothing bad happened.
Keep an eye on who can see what in your calendars!