I've searched and not found an answer for this question: Can I hang my house and work keys on my Prius smart key fob? I read the owner's manual and saw where they said NO metallic objects near the fob. I wanted to see what your real world experiences have been. Today is my first day with my beautiful Blizzard Pearl 3. Excited! Thanks!
You can hang those other keys off your smartkey, but you'll need to take it out of your pocket to use them.
Hmmm... Never noticed before that the manual for my 2005 said the same thing. My smart key lived on a ring with my house and mailbox key for 7 years. It's been replaced now by the key for my new 2012. I wouldn't wrap it in foil, and would definitely keep it away from magnets. Otherwise I wouldn't worry too much. Enjoy your new Prius!