User blog comment:AYET/Talk about chapter 716 and episode 604/@comment-6920514-20130731215558/@comment-6920514-20130801125124

AYET, I think Shanks definitely knocked out Coby on purpose. He blocked Akainu's attack with his only arm (and saber) and put the kid to bed with his haki as his way of saying "you've done enough." or "that'll do pig, that'll do"