A invention that I really like is one of those gps bracelet. I think that it may be the solution to worried parents. If my kids wore those bracelets everyday I would never need to worry about where they are or if they'll come home again. If I get a bit worried I just look up their location on the internet through the bracelet. That way I can always know where my kids are. It's a really great little thing that bracelet. So I can really recommend you getting one if you're worried about your children.