Pigs eat grass if they are very hungry, but they can't use it as a regular source of food.
Would I buy a cell phone for my 12-year-old?... No. I should have closer control over my child than that. He really shouldn't be in places where he needs to contact me by cell.
It's kind of part of human nature to want to know the truth or want to be in on the secret. For stories that focus in on that - like whodunits - it's easy to get drawn into.