User Calendars and Task Distribution Management

Good day BPM Forum,

We are busy designing a process with Queue Task Distribution Management incorporating the user Outlook Calendar.
The part of the solution we are not able to confirm at the moment is in the case of a user leaving the office during a business day (for personal/sick/etc.) and does not set an ‘Out of Office’ rule on the user’s Outlook Calendar.
How can we solve the problem of marking the user calendar as Busy or Out of Office with out having to set sharing of privileges on the Ms Exchange server side from BPM or MWS to allow a supervisor or team leader to manage the user in the team.

A Simple solution we are toying with is to just book a full day meeting with the user that is not available anymore, however this is not a confirmed meeting but still in ‘Tentative’ state in the user calendar. But will the Task Distribution recognize the ‘Tentative all day’ meeting and not allocate task to the user?

Any input or advise will be appreciated.