This happened to that person's child? Really? Because what you've just described is a fairly well-known urban legend. (Although the last time that I heard it, it was at Wal-Mart, not Disney, but the mom still identified him by the shoes.) It showed up in "The Vanishing Hitchhiker" and there was a Law and Order episode with that plot as well. I think that if you talk to that person again, you'll find that it didn't really happen to them, but to "someone they know."
Why look at the shoes? Why not just look for the kid with dead hair?
SD
Because all kids have dead hair. So do all adults.