Not quite true.
Staff (including myself!) have been asked to volunteer to take units of either a week or a month, as either additional unpaid leave or unpaid work.
It IS optional, and staff must physically respond to the request by choosing an option online in the staff intranet. This can be to decline to tae any option, or to choose a specific week/s or month/s to take.
The reason for offering unpaid work, is believe it or not, some staff said they didnt actually want any more leave, and would prefer to come to work anyway.
So, if you dont want to work for nothing, you can opt for the additional leave, so there would no need to get yourself into trouble by not showing up!
Regardless of whether paid or not, any staff member who fails to show up for work, in any job, is subject to disciplinary action, regardless of any financial consequences.