I just got a 2018 MacBook Pro with the new T2 chip. I'm passing information this along as a general FYI... When booting up my new MBP, the keyboard backlight and the Touch bar wouldn't turn on for the login screen. No Touch Bar, so I can't adjust the keyboard backlight. I find this annoying as I'm still getting used to the new keyboard and now have to turn up the room lights so I could see the keyboard while entering my password. Apple Support confirmed this behavior is because of having FileVault enabled and how the T2 chip behaves. Apple's expected behavior is that when FileVault is enabled, the laptop's boot up behavior is changed. When the MBP is initially turned on, the Touch Bar and the keyboard backlight will stay off until your password is entered. Once my account password is entered, it then will continue booting, the keyboard backlight and Touch Bar will then turn on. I tested this by turning File Vault off, and the keyboard backlight turns on for the login screen during the initial boot up. I still can't use the fingerprint sensor for the initial login though. Like the iPhone, you have to enter your password for the initial login.