There's no question of a hack, although it might not be necessary to hack the door lock, you might be able to unlock the house from a phone you pick up off the table in a coffee shop. The phone would not even need to be open.
"August locks provide keyless entry based on the Bluetooth. You can also configure your locks to lock the door after you leave the home. It senses when you approach the door and unlocks it automatically, no matter whether your phone is in your pocket, purse or a carry bag....Guests also need to install the application on mobile phones. Once guests have the application with the assigned rights from the owner, they can use it for opening the lock."