It appears that inputting the wrong Apple ID email address could lead to an Activation Lock with the new iPhone 7 and iPhone 7 Plus and some iPhone 6s and 6s Plus models.
A number of users have stated that, after entering the wrong Apple ID email address, they cannot sign in and are therefore unable to proceed with setting up the iPhone. The issue has primarily affected new iPhone 7 and iPhone 7 Plus models upon being turned on for the first time, and iPhone 6s and iPhone 6s Plus models upon being restored to default settings, although older models appear to be affected to a lesser extent.