Establish a code word to be used if a stranger picks your children up from school or friend’s house. Many people recommend this but almost nobody does it. Worse still, nobody checks with their children to see if they remember the code word. Check, drill, check again. Make it a game. Let the kids use it against you. Whatever it takes. Also, if you have (as I do) an emergency substitute you can send to pick up the kids, be sure they know the code word too. If you are divorced or separated and have custody issues this is a good technique to use, with some modifications to fit the situation.