In April 2018 when we first got our Model 3, it would unfold the mirrors and unlock when you approached like shown in that video. Since late Summer 2018, the behavior changed and there is no outward appearance that the phone is in range. When the phone is present within range and you pull the door handle it will open. If the car does not have a connection to a phone within range, when you pull the door handle it will put up a message on the screen to swipe the card key. If you do have the phone but it's not recognized, the most I have to do is open the Tesla app and it will make connection. The Bluetooth phone-as-a-key used to be much more of a hassle. It works quite well now after several software updates to specifically address those issues.
Basically, the OP's concern is a non-issue to me since I park in an attached garage. Other people who park very close to the house but in an insecure area may have a valid concern that the car might unlock if someone tried to enter the car while the phone was in the house near the car.