960design
macrumors 68040
No they would NOT need to be online. BUT, the device may or may not attempt to connect to the strongest WiFi in the area. You can see this on passcode locked iPads: sometimes the WiFi will be on before you enter a passcode and sometimes it will not.They wouldn't need to be online to do that right? It's just an option in the settings
Depending on your settings, 10 failed passcode attempts may wipe it for the thief and allow them to set it up as a new iPad. I've sent several emails to Apple engineers in the past over this issue.
The Apple guys put a lot of thought into the activation lock idea. They just need to add one more feature: a supervised device should be able to remove the activation lock through an MDM.

