Port Blocking Goes Wireless

I've been a long time advocate for the prevention of Port Blocking both here and on KenRadio.com's World Technology RoundUp but based on this TechDirt report it seems Port Blocking is now going wireless.

Just like Port Blocking by broadband providers of Port 69 effects a small minority of those desiring VoIP services, it seems a telephone Co-Op in Iowa is going to stop allowing cellphone traffic to terminate to their customers.

This is a very interesting situation because it is all about money or not getting enough. What makes it interesting is that Wireless telephony likely falls under the FCC Telecommunications Act of 1934 which was updated in 1996 and thus intercepting the call without authority vested by the FCC is likely prohibited. Unfortunately not being a telecom attorney, I'm not sure while in principal what they are doing is Interception or blocking, just where and how the FCC Act would apply.

So here's the Post Hoc Ergo Protor Hoc argument (if this therefore thenfore that) as my old Professor Dr. Towne the Chief of Confussion would put it.

If it is illegal to block a transmission without authority, how can any company block a port?

Legal scholars, your opinions are sought.