I have one account set up, just the admin account made when I bought my 2012 MBA I currently have "Find my Mac" enabled, but I was thinking if someone stole my MBA and I wanted to use this feature to locate it how would I do so if the thief can't even access my computer past the login screen? I know Wifi needs to be available but lets say the thief is sitting at my login screen trying to figure out a way in, would Find My Mac still work? What if I set up a guest account, would that help anything? Or what if the thief figured out how to wipe my system completely and create a new login account? I am curious about this because my home was recently burglarized and the idiot robber was too stupid to check my room and take my MBA so I got lucky. I didn't have Find My Mac enabled at the time so I want to know how useful it really is.