Attendance list of a sprint should be private, or attendance should be markable as private

I'm sure you're aware of the recent "Death by Google Calendar" scandal <http://dumblittleman.blogspot.com/2006/09/how-to-get-robbed-killed-or-stalked-by.html> where somebody had unwittingly published information on Google Calendar that indicated both who they were and in particular, when their house was empty.

In the wake of this, insurance companies (including my own) have been adding clauses to their policies that state if one whether deliberately, or by mistake, publishes information on a public calendar on the Internet that suggests their home is empty and a break-in occurs, they are not insured.

Basically this can mean that if I mark my attendance in Launchpad at the next sprint, my house and its contents will be uninsured for that period.

I would therefore like to be able to mark my attendance *private*, so that it is only viewable by other people attending the event.