The current field control system uses virtual LANs to simply re-route packets in an identical fashion to what teams are doing today with either tethered or WiFi operation. FIRST is reserving the right to enable additional layers of security (eg an SSID with WPA key or similar) but the intention is always to make this as seamless as possible for teams to migrate from development to competition. Unfortunately, there isn't a really easy way to pass around secure keys (and keep them secure) but there are ways if needed.
If anyone has a faulty Digital Sidecar (especially such that the RSL doesn't appear to be functional), Eric and I would love to have the opportunity to test it out.
My understanding is that AndyMark is expecting to handle replacements but, of course, we need to be simultaneously sensitive to team $, teams' need to keep running and AndyMark's $ (eg replacing sidecars that simply have a known loose capacitor that doesn't result in any other errors).
As I've written before, I would strongly encourage teams with non-functional sidecars to utilize the FRC Diagnostic Window utility at the following site to test the operation of their module before sending it in for replacement/repair.
http://thinktank.wpi.edu/article/138
Russ