Basically, the guys take was to have a line that the carp could see. His premise was that Carp do not spook when they bump in to limbs and such in the water, because they see it's there. However, when they are swimming along and bump in to a line that is "invisible" underwater they spook because they are sure what they hit.
Let's hear some of your takes out there on this topic.
Gotta link to this artical?