At Google I/O, Google introduced Personal Unlocking as part of the Android L as a way to keep devices secure, but not overwhelm users so that they don't want to set up a security system on their phone. With Personal Unlocking, Google will be incorporating features like location and connected Bluetooth devices to ensure that the phone is in safe hands and not in the hands of thieves.
Location: For example, if you've designated a secure location using GPS, like your home and office, then you won't be bothered with a lock screen that begs you to enter a PIN, passcode, or pattern to unlock. If you're outside of the geofence, then a lock screen will ask you for your passcode as a secure measure. This makes it more manageable for consumers who want a secure phone, but don't want to be annoyed by security when it's not needed, especially if the phone is being unlocked to be used at home.
Bluetooth: Another way to manage Personal Unlocking is to connect to trusted Bluetooth devices. If your phone is connected to your phone's Bluetooth, or your Bluetooth wearable--like your fitness band or your smartwatch, then you won't need to enter a passcode. Your Bluetooth connection serves as a key to unlock your phone, making it more convenient. If you walk out of Bluetooth range, then whoever picks up your phone will need to enter in a password to unlock the device.
Is this a feature you're excited for in L?