While pondering the functioning of trace in the wireless matrix, it hits me that access id is not tied to node but persona.
This means that although you can analyze a persona to get a access id, take tells you exactly nothing about the node the persona originates from.
So this means that in order for a spider to counter hack a hackers comlink, he first needs to run a trace to know what node to attack.
This because the nature of the matrix is that the traffic routing happens via access id, with the go between nodes not caring about the end node. They just look at the access id, and either send it to the last known other node that handed it some traffic from the same id in the past (if that node is still in range), or sends out a general "can someone please forward this?".
So in a sense, access id is more like a mobile phone SIM. I can swap the phone, i can swap the number, but as long as i have the same SIM any call, text or similar directed towards my number will reach whatever phone i happen to have my SIM in at the time. But for all the caller knows, i can be on the other side of the planet thanks to network roaming and such.
So it may well be that some squatter has a access id without owning a comlink. This by having some kind of card or similar that holds his access id, that he then uses when buying matrix time at a matrix cafe.