Non-root backup with multiple users (non-owner or secondary users)
If you are on Android 4.2.2 there is a way of unlocking the bootloader without wiping the device. Use towelroot to root your device. (It works on a neuxs 7 as long as you have a kernel build &lt; Jun 3). Afterwards you can use the following app to unlock the bootloader (It doesn't wipe the device). Then you can use titanium backup to backup everything on your device, even when logged in as a secondary user.