Turning off the car is bad. You lose power stearing.
In any modern car, though, the breaks will overpower the accelerator. There's no excuse if she wasn't pushing the breaks. Ticket + driving school should be in her future.
Yes. You lose power steering, but if the car is rolling, even without power assist, the steering is easy to turn unless you have some form of physical disability.
The power steering went out on one of my old cars a while ago (burst pipe). I just cut the belt off (to avoid damaging the pump which now had no fluid in it) and drove it for the next week until I could get it booked in for someone to repair the pipe.
Sure, the steering was a bit stiff when parking - but when the car was rolling, you didn't really notice much.
I've also noticed some comments about shift locks. It's possible that things have changed in the last year or so, but even in 2010 cars, I've NEVER seen any form of transmoission lock between Drive and Neutral - at all. If you are in Drive, you can always shift to Neutral, there is no need to press the button on the selector stick, no need to press the brake. Other selections may be locked (e.g. Park to Reverse is locked unless the key is in, brake depressed AND selector button pressed). Certainly in a Lexus, there is absolutely no restriction whatsoever in shifting from drive to neutral - you can always shift just by nudging the lever - no buttons, no brakes. I'd imagine that a Camry was similar.