Apple has sneakily added a new function to OSX Lion, currently in the hands of developers and due to launch in a few weeks, which could help owners of stolen Macs to retrieve them.
The biggest clue as to the nature of the new 'Safari access only' feature is the fact that is part of the Find my Mac app, rather than the network control panel.
Basically it allows a 'guest' (or thieving toe-rag) to access the Safari browser from a password locked OSX computer and nothing else. Although the new function has obvious uses for in-store demonstrations and kiosk-based hardware, it's in the hands of uninvited guests that the new addition becomes more interesting.
Find My Mac allows users to locate their missing hardware using geolocation, post a message to the Mac's desktop or even wipe the entire contents of the hard drive remotely. Unfortunately, all of these security measures can only be carried out if the hardware in question is running and connected to a network.
So while the individual who liberated your precious hardware is unlikely to be able to access your Mac's innards before it falls into the hands of someone with the technical nous to do so, he might just, given the opportunity, do a bit of web searching for clues on how to bypass OSX's security, for example.
Although Apple would probably never admit such an intention, it's a clever little honey trap which will allow users to trace the location and even IP address of the miscreant currently in possession of their property.