> Access to a network may be denied when the modification itself materially > and adversely affects the operation of the network or violates the rules > and protocols for communication across the network.
The way I read that is that it is the unit you are on will have it's radio off,
I think you have misinterpreted those words. Denying a user or a machine access to a network means cutting off communication in the network, not altering the machine.
This clause is not an exception to the requirement for installation information. Cell phones must offer installation information just like other User Products.
This clause says that, if a phone network operator sells you a phone with GPLv3-covered code, it does not thereby promise to continue trying providing service to the phone if your changes cause it not violate protocols and mess up network service. The operator is allowed to cut off service for this phone as it would any other malfunctioning phone.