I'll have to take another look at the manual for that warning. I can see where a strong RF field might overload the Smart Entry/Smart Start receiver and desense it. But if I'm already in the car that might not be an issue. If you have the car in Ready mode and leave with the fob in your pocket it beeps a few times, but continues to run OK. So it might not be an issue other thaty perhaps not being able to use the Smart Entry if the transmitter was keydown.
Sounds like quite a smart nav. system. I probobly would have liked having that feature. But didn't want to upgrade from package 7 to 9. If I could have gotten 7 plus the nav. that wpold have been different.
My overall milage runs 46-49. My wife does a little better getting just about 50. She's better looking too!
How about a photo of you and the new Prius?