iPhone passcode security
One a malicious individual has physical access to the hardware, any protection becomes meaningless, security-wise. 

If an attacker had the time and resources, they could circumvent any UI-based security by removing (de-soldering) the flash from the logic board, connecting it to another system, and reading any data off them. Only full-disk encryption would block that, but, given physical access and/or time, that's defeatable, too.