I've left my phone in the car many times over the years. If I am concerned about someone seeing it, I'll put it under a piece of paper or whatever is on the passenger seat, or in the console. Never had a problem with this technique EVER in my 2011 Challenger R/T.
I emailed Tesla's feedback line back a few days ago with my issues and suggestions for improvement. Haven't heard back yet.
Tonight, the phone was opening the door but not starting the car. After a long day of work at home with an electrician and going up and down stairs many times, my knees and feet were on fire and hurting. I went to the store, came out, got in the car, had to twist to the right and dig the key card out of my pocket to start the car. Then while putting the card back in my pocket, I twisted too far and took my weight off the seat too much, which shut it down. So then I had to twist again, get the card out again, and start the car AGAIN with the card, because phone-as-a-key SUCKS!!!
I'd be willing to pay $30 or so for a fob, but seeing as how I just dropped $50,000 on a car, maybe Tesla could discount that $30 by $30 or so.
Someone suggested turning off Bluetooth on my phone. Too much hassle to turn it on and off all the time, plus I never turned it on ONCE in 3-1/2 years, until I got my 3.