I saw this the other day and I thought to myself, this is a great idea.  I wish I, or someone else, had thought of this when my kids were smaller.  Nowadays, they are pretty capable of spouting off more information about who they are or where they live, than you are really comfortable with.

According to huffingtonpost.com, here is what you should do if you plan on taking small children somewhere where there will likely be a large crowd:

Write your phone number on their wrist and cover it with liquid band aid in case you get separated. Also, take a photo of them using your cell phone the morning of the event so you have their clothing, hair style, and up to date photo.

The article goes on to say that you should take a photo that day so you can show exactly what clothes and hairstyle they have that day.

You never know what could happen in a crowd.  Hold on to your kids, but you never know when someone could break your chain