Trust is something earned, not given freely. And these days, its so much more important to ensure the safety of your own than it is to freely grant them their privacy. IMHO. Mine are young yet (6 and under) but I feel strongly about this. If they are good and upstanding then they will be granted privacy. If they are having troubles, its my duty as a parent to do whatever I can to discover what the problem is and how to correct it. If that means reading a diary or listening in on conversations, so be it. They will be told this and hopefully understand the priveleges they are granted or denied.