From the link you just posted, the owner knew of this loose shoe at latest on Saturday, June 8.
http://hoofcare.blogspot.com/2008/06/big-browns-owner-says-loose-hind-shoe.html
Seems kinda like Tanya Hardings undoing in the Olympics was a loose shoe string on her skate, wonder what else Tanya and Bib Brown have in common
Ah - SO it’s not a surprise that it was loose.