Take a picture ...

Great tip from a US sheriff's office, sensible with all children, but particularly with those inclined to wander ... some of you might already do this:

Before leaving home with children and/or grandchildren for a large event, take out your mobile phone and take a photo of each child individually. That way, if the unthinkable happens and a child gets lost, you have picture with you of how they are dressed and how they look that day.