The point of the pledge is that you take it and you encourage other parents in your school/neighbourhood to take it. So this helps solve the coordination proble

The point of the pledge is that you take it and you encourage other parents in your school/neighbourhood to take it. So this helps solve the coordination problem: "By signing the online pledge, you promise not to give your child a smartphone until at least the end of 8th grade as long as at least 10 families total from your child’s grade and school pledge. Once 10 families have pledged to delay the smartphone, you will be notified that the pledge is active! You will receive a list of families who are delaying from your child’s grade and emails for the parents."