On a Model S, sometimes the door handles won't present, BUT you can open the trunk. Before you start worrying try the trunk. Yes, its a pain to crawl though, but sometimes it works.
Do yourself a favor. Take your car home, find both your fobs or keycards. Get your phone. Roll the windows down on your car, and then test. Leave your fob or keycard or even phone in the car and try opening doors. Check your owner manuals. Some exterior places work better than others for reception. Be advised, keeping your smart phone near - same pocket, in the purse, in the same back, on the console near your fob, will block the fob's signal. It will interfere with it.
I remember reading a long time ago, about an owner had left his fob laying on top of his smartphone on the console. He described using a clothes hanger to pull the fob off the phone and into the car's floor and then he could press the handle and the handles presented.
You 3 owners - there's no excuse for not having a spare keycard. There's no excuse for not having it where you can have a friend bring it to you. There's no excuse for NOT having more than one spare.
Don't forget, just because you don't have your own phone does not stop you. A stranger will let you borrow and download the app to get into your own car and even start it just to have a story to tell about a Tesla owner. Before you had it back, delete the app. Or when you get home, change your password. BUT know your password so you can login from a different phone.
You young'un's out there ever hear of Murphy's Law? What can go wrong will go wrong? If you practice locking and unlocking your car with your phone, your keycard, your fob. Find out the limitations and think it trough before you need it, it will be easy-peasy to get in your car when its locked.
