Disney is great at finding "lost parents"!
Teach your kids to stay put if separated and how to recognize a CM and ask for help. Take a quick photo on your phone before heading out in the am. Many times, this happens when each parent thinks the other has x child and wires get crossed, make sure to communicate who is going with whom if/when separating etc.
I used a "Disney theme dog tag" on my kid's shoes with my cell number until they were old enough to remember it. They are small but CM's will notice them and be able to get the info without touching the child. I still buy them but now I use them on my luggage