Privacy and Google's Latitude

Google has just released Latitude, a a service that lets you keep track of where your friends are by tracking the whereabouts of their mobile phones. Latitude is available in 27 countries. The following phones are supported: Android-powered devices with Maps v3.0 and above. G1 users in the US will be receiving Maps v3.0 in a system update soon. Most color BlackBerry devices Most Windows Mobile 5.0 and above devices. Note: Some Windows Mobile devices don’t support cell-ID location detection. Most Symbian S60 devices iPhone and iPod touch devices with the Google Mobile App (coming soon in the US) Many Sony Ericsson devices (coming soon) (From Pandia) It is opt-in. Will Google be 'on top' of the privacy issue?