Toyota keys (why do they lock themselves in the car?)

These are the key fobs that lock themselves in the car!
http://www.bild.me/bild.php?file=4828475keyfob.jpg

It takes one key to open the car, and two of those doohickies to start the
car with the one key that opened the car. I don't understand why.

Anyway, I borrowed a friend's Corolla for the weekend and just now I had to
ask her to let me back into the car because the car locks itself after an
unknown period of time without any user intervention whatsoever.

What's with that?
She says the car locks itself all the time on its own schedule.

Is there a way for her to turn this off so it can be normal?
Is there a way to make it so that just the key starts the car?