I bought a set of RoadID's for my kids. We use them every time we go to DLR.
http://www.roadid.com/Common/default.aspx
I can't recommend these enough. We have used other items in the past, and they all don't hold up. These ID's are super good quality, and the customer service is beyond amazing. You can put on the ID names, phone numbers, and special info like the fact my DD has asthma, and that my DH is allergic to penicillins. Seriously, get these.
Ours actually came in handy once. We were in DL, near the exit from POTC. We started walking toward Splash Mnt. Everyone, except my DS, started walking. By the time we got to the Haunted Mansion, we noticed he wasn't with us. Of course mommy panic sets in. I started running back to where we had come from, as my cell started ringing. My DS had walked up to the cart that sells the cute decorated parasols, told the CM he couldn't find his mommy, and showed her the bracelet. She called me, we were reunited without incident. Kids can remember their street address and home phone number, but not many know their parent's cell. And when they are freaked out and lost, it's that much harder to remember. I have always taught my children that if they are lost in DLR, find a grownup with a name tag. ALL DLR CM's wear them. You can get help from them.
Also, if you decide to get a Road ID, let me know. I have a coupon code for 15% off through 10/1/13.
GET ROAD ID's!!!!!!