And that statement makes you look dumb. Naruto sensed the presence of another person. Tobirama sensed the presence of another person. And now you say Shee didn't sense Genjutsu, implying that sensing a human is the same thing as sensing the usage of a Genjutsu. Minato also sensed Naruto at the battlefield, does that put him on the same tier as Tobirama in matters of sensing?
@KidGamer, Genjutsu manipulates the Chakra in the victims brain and disturbs his senses. The eyes (eye contact) is just the medium which gives Itachi access to the chakra of the victim to be manipulated. Is Itachi focusing chakra into his finger when using finger-Genjutsu? Where is Kurenai focusing her Chakra to let the victim perceive visual Genjutsu? Where is Hashirama focusing his chakra on to create the Bringer of Darkness? Where is Itachi focusing his chakra on when using Izanami against an opponent like Kabuto, who blocked his vision?
Kabuto was a Sensor, too, with the Sage Mode a great above. So why blocking his vision if he, with his great sensing abilities and his perception of danger could sense a potential usage of Genjutsu and in this moment just avoid the eye contact? He, knowing that an eye contact automatically ends in a Genjutsu was reason that he blocked his vision.
It's not that simple with Genjutsu as with Ninjutsu.
