As far as I understand http://en.wikipedia.org/wiki/Cybernetics , the planner must be able to actively communicate to you before carrying it makes you a "cybernetic organism".
But, like all other definitions it can look useless when stretched to technically apply to specific situations (like the laptop-on-back example).
For instance, my refrigerator is technically interactive by the definition of reactive interactivity: "A message is related to one immediately previous message", where my messages consist of opening and closing the door, and the refrigerator's messages consist of turning on or off the interior light.
Saying my refrigerator is interactive is technically correct, but useless and silly. Still, the definition for reactive interactivity is useful and popular (at least in computer science).
I don't think that the idea of carrying a laptop making you a cyborg is any more of a stretch than the idea of carrying a smartphone making you one. Laptops and smartphones are similar in capability, mobility and proximity (given the laptop/backpack example) and certainly in interactivity.
I am curious what it is that qualifies a smartphone as an "exobrain" that also disqualifies a laptop?
