Hilariously, that idea leads to a personal note. Togusa details that Yoon-Sung the self-proclaimed rich jerk hacker cracked his cyberbrain's security. The resulting prank was a harmless one, but it showed Togusa that he could be hacked. (He follows it up with a note that Yoon-Sung has installed a firewall of his own company's design to prevent this happening again.)

But it's brought up a lot of questions. If the micromachines can send a signal out, someone could track Yamaguchi with them? Can someone send a signal in? And literally change what you see and hear? There is a note of it happening to androids in the other Togusa's world. But only guesses that it could happen to him.