You cannot open the Tesla app or buy anything from Tesla without inputting your credentials. If you think you can it's because you are confusing switching open apps with opening an application. Yes, you can leave the app open, that is different from opening the app and is why phones are generally configured to auto-lock. I'm surprised that, as an app developer, you are unaware of these basics and the difference between app switching and opening an app.
I'm for however Tesla wants to do it, as long as it's convenient for me. After all, it's their business to run. If I don't like it there are plenty of other companies I can go to to take care of my auto needs. I was born in a time when most people were raised to take responsibility for our actions and we were not guaranteed to win every contest as a child. If you came in last, you lost. Simple as that. Now kids are raised believing everyone always wins and you don't have to take responsibility for your actions (like leaving an unlocked phone in the hands of a toddler). Think about this:
If I put my property tax payment in my mailbox but my 2 year old toddler gets into the mail, pulls out the envelope with the check and drops it on the ground where my dog eats it, my tax payments are going to be late and it's going to cost me a few thousand dollars. If I go to the County Assessor and explain that I put it in the mailbox on time, I had the money in my checking account but due to unforeseen circumstances my toddler removed it from the mailbox and I would like an extension, it wasn't my fault.
But he will politely explain to me that it's my job to ensure the chain of custody of the payment and they cannot forgive late payments, even if only a day late. It was a $5,000 mistake. I could have used registered or certified mail, delivered it in person or watched my toddler more closely but I messed up and I owe them $5,000 dollars. There is no grey area here and I know that. Some people, mainly those raised in the era where "everyone gets a prize" are flabbergasted at how unfair that is, to people like me and Elon, that's normal, you have to take responsibility for your actions (or lack thereof). We did not grow up getting a prize for crossing the finish line last! We know that you have to know the rules of the games you play. No one is going to do it for you.
Having said all that, Tesla regularly forgives people who make honest mistakes. This woman will almost certainly get a refund. If not, it's only because Tesla determined beyond a reasonable doubt that she is not being forthcoming or honest with them.
Know the rules of the road and be responsible for your actions! It's not difficult. I love Amazon's easy order process and every time I've bought something from the Tesla store I appreciate that my computer fills in my credentials for me, just as my phone does. Let's not lose that benefit simply because someone was raised to think they don't have to take responsibility for their actions. The amount of privilege people expect these days and the lack of personal responsibility is unbelievable!