why would you want this?
Seems like it would inconvenience you and it won't do anything to stop a halfway decent thief.
Because I was in the apple store the other day and two people were talking about their phones.
One lost his in a bar and the other had it stolen.
They tried to log in to iCloud to search for it but couldn't as any decent theif will simply switch the phone off.
Having some barrier to that is worthwhile.
It wont completely prevent anything but good to have an additional layer of security IMO.
Most thieves will try to check it out and play with it and not sure they would know how to enter DFU mode.
Hope by that time you can start tracking it if you catch it early.
Because I was in the apple store the other day and two people were talking about their phones.
One lost his in a bar and the other had it stolen.
They tried to log in to iCloud to search for it but couldn't as any decent theif will simply switch the phone off.
Having some barrier to that is worthwhile.