ultimately parents need to be responsible for what they put in their child's hands and what they do with it. Apple does provide controls for restricting use on their devices and it is up to the parents to learn about those features and enable them or not. Unfortunately passing the blame game is all too common anymore which only serves as an education for your kids to do the same. man up and parent your kids properly instead of blaming others for your problems.
Hey, it could be your grandma, accidentally clicking the OK button within the 15-minute window. Or it could be you, for all intents and purposes of this discussion. Nothing to do with parenting, be it good or bad.