See other failures under 000.html.
From http://www.rotorburn.com/forums/showthread.php?198438-Thank-s-Shimano as of 2013/08/24:
Posted 2010/01; "Hone" model cranks, history otherwise unknown; rider was not the original owner.
Rider 100 kgf. Failed while bunny-hopping. Rider not injured.
A follow-up post says the triples have an aluminum spindle while the doubles are steel, and the poster seems to think the axle on the triples is much more prone to fail.
See also FAIL-186.html.