I have just seen a piece on GMTV called "Tag your Tot"
when you go on a beach you enter the tag your tot number into your mobile.
then you put a wrist band on your toddler and write your mobile number on there wrist.
When your kid goes missing you call the number and a life guard comes to you to get a discription of your kid and then a search begins.

Heres an idea how about actualy interacting with your kids , playing and talking with your children enjoying your holiday together as a family and not being so obsessed with your own tan (or getting drunk)that you let your kids wander off!
These sort of people don't need a Tag scheme no doubt to match the one they have on there own legs but they need parenting classes.