I always figured it was so that they could prevent the talent from seeing their, "Oh we've got such and such a job offer at blah", statement and then they just

I always figured it was so that they could prevent the talent from seeing their, "Oh we've got such and such a job offer at blah", statement and then they just go and call up blah and say, "Hey, I heard you guys might be interviewing for a position." Because if that happened, they wouldn't get their cut of the hire.