First, it isn't clear how you request a specific item or file from the network. You can request the USB stick, but who knows what will be on it.
Second, SMS traffic is already tracked for billing purposes, and is tied to a phone number with a billing address (most of the time). It'd be even easier to identify the users of this network than most online networks. You wouldn't know what was being traded without intercepting the USB stick, but still.
Communication regarding file requests are on the Wiki, which is on the USB stick itself. As for your privacy questions, see the section "privacy" and "handbook," deadSwap trains people to be clandestine, it is the behaviour of the people, not the technology that makes the network work, or not.
Second, SMS traffic is already tracked for billing purposes, and is tied to a phone number with a billing address (most of the time). It'd be even easier to identify the users of this network than most online networks. You wouldn't know what was being traded without intercepting the USB stick, but still.