What happens if a contestant's phone turns off?
I don't think the requirement is strictly for the phone to always be on but rather that it shouldn't get damaged. The phone is meant to be a reflection of the user, like a piece of their soul. So if it's damaged, the user is also affected. It probably doesn't hurt to just casually turn it off since it doesn't harm the phone. Although, it would be a BIG disadvantage, lol! I would guess the power would work the same too.