How about a big helmet? I imagine snowboarders/alpine skiers/motorcyclist will have to take off the helmet to unlock. As someone who goes snowboarding in the winter, it sounds really annoying to not only have to remove a glove, but also the helmet, to unlock the phone (or unlock with a passcode, which is still a downgrade from using the fingerprint).

It's starting to sound a lot like:

    if (true) {
      unlock_phone();
    }