Please correct me if I'm wrong.
As I see it, Slaving Devices to a Commlink or a Deck, is basically the same as having a proxy nowadays. Even if you are a Team of 3 people, when everything is slaved to one Deck, its just one Persona Matrix wise. This Persona should be a lot better in defending your stuff, as getting marks on it will place marks on everything within that network.
You can use your stuff as usual, but all communications between your Personal Area Network (PAN) and the wide wastelands of the Matrix go over the "Proxy-Deck".
Somewhere the Book states that Commlinks have only 3 Attributes: Data Processing, Firewall and Device Rating. So neither Attack or Sleaze. Enemy Matrix Perception against Intuition + Sleaze should make it impossible for you to stand undetected without a proper Cyberdeck. Your Commlink can only help against direct attacks with its Firewall attribute.
If an enemy has Marks on your Decker, he can do all sorts of silly stuff to you. As I would allow your Decker to torment you (and your gear), if he pleases. I would see it as 4 Marks for you and the owner of the PAN on the Device and a Mark on the Deckers Persona equals to Marks on EVERYTHING (as it works in Hosts) and a direct Connection to i.e. your Gun overrides protection of the Deck.
You can do the same to enemies.
