I dunno, maybe not but I just thought I'd throw that out there.
Hacking a chip to turn on and off would be a feasible feature, considering the chip is controlled by the mind.
Automatically rotating serial numbers or aliases might be a way to make the chip harder to trace at the expense of not being able to receive incoming messages.
Back to darknets, a nice way to implement this is to release SIC transponders in game. First a person would need to get their chip hacked to allow adding and deleting of transponder links. Once the user has the capability to add a network they simply need to know somebody who has a SIC transponder and get the connection codes. Any message sent to that transponder would then relay to everyone else connected. In addition, the owner of the transponder also has access to private messages sent between individuals >:( as would the owners of any other transponder on the same network. New commands would be similar to 'who network-name'.