Inspired by discovering a well-known DiSer didn't think it was important. Someone picks your phone up and it's not locked they can make ridiculously expensive calls, for which you'll be liable until you've reported it to the police, and they can also go into your email, facebook, Twitter, etc. and basically fuck up all your stuff.
I did note how far too much of the Bridge II plot was moved on by people in powerful positions who didn't seem to think there was any need to lock their iPhone ever. I didn't even know Apple let you not have a lock.