This was something that I did with my kids years ago. I deleted the link after they became adults. The alerts that I received were usually when their name was in the paper or when the high school posted a newsletter online. Occasionally, Google alerts would come in for people who had the same (or very similar) names to my children.
I didn't think of the alerts as being a safety measure. For me, it was a way of helping the kids find things for their scrapbook. As Bill points out, Google alerts can serve another purpose. By letting parents know when their child's name is used, parents are able to better monitor their kids behavior.
Setting an alert is as easy as going to www.google.com/alerts and following the directions. It only takes a few minutes. If it helps protect children, then it's a few minutes well spent.
It is a very good idea to Google your Child's name once in a while or setup a Google Alert for His/Her Name. What are they doing online?
— Bill Latchford (@PCOorg) September 15, 2014