One of my kids has special needs. This means he rides a certain bus and goes to a certain school. It would be trivial to uniquely identify him for the rest of his LIFE with only the information contained in my contacts list.
So now, without consent, this "private" "friends and family"-based app I installed on my phone, plus it's company, plus any other company they choose to do business with, or any entity that acquires them in perpetuity, or any data mining, social profiling, credit bureau, can start building far-reaching and long-lasting profiles of a four year old little boy that needs a extra help.
What part of that confuses you?
p.s. this could have been avoided with a dozen lines of code via a dialog box.
