If the battery is in the trunk on a BMW automatic, park the car in a garage backwards with the car nearly touching the wall with the trunk. Stop it (parking brake engages). Wait for the battery to break beyond the point of recharging it by letting the car sit still for some months. Congratulations, you've successfully soft locked your car. You can't open the trunk, because you can't move the car forward, because you can't put the car in neutral and release the parking brake, because you have no power.
With brake on it's not uncommon for them to stick to the brake disk coz of rust + humidity, at best it will be PITA to get it moving again, at worst it will do some damage.
