It may be as an anon has pointed out, to prevent the child from being able to run. Besides if a child keeps falling down, you simultaneously break their will. Satanists love setting things up to make people feel stupid and helpless, while giving the appearance that it is an evenly stacked deck.
I'm sorry, my second link is (pb), I forgot it was still on there.
If you wanted to hide children's footprints, wouldn't you use the entire shoe?