I may have an idea on this.
CODE ADAM is a signal for a missing child in a store, theme park, etc.
It is announced to all staff over PA or walkie.
FIRST thing you are taught to look for is the shoes. Too hard to switch.
Kidnappers will change shirts, cut hair even, but they can't or don't have time to change shoes.
This picture made me think of that.
Not sure if relevant but I wanted to throw it out there.