You're correct--Comcast is in direct violation of FCC regulations by encrypting any rebroadcast of local over-the-air television.
Code of Federal Regulations Title 47, §76.901(a) reads:
Basic service. The basic service tier shall, at a minimum, include all signals of domestic television broadcast stations provided to any subscriber (except a signal secondarily transmitted by satellite carrier beyond the local service area of such station, regardless of how such signal is ultimately received by the cable system) any public, educational, and governmental programming required by the franchise to be carried on the basic tier, and any additional video programming signals a service added to the basic tier by the cable operator.
CFR Title 47, §76.630(a) states:
(a) Cable system operators shall not scramble or otherwise encrypt signals carried on the basic service tier.
The first regulation requires any rebroadcast of a local over-the-air station to be included with subscription to the core basic services tier. This is the lowest level of service to which you can subscribe and to which you are required to subscribe to get anything else, so if you have cable service you have all of the local channels on the system, including the ones broadcast in digital form. The second regulation states that nothing in the core basic services tier can be encrypted. So if you subscribe to cable at all, you should have access to rebroadcast DTV channels and that they must be transmitted in the clear.
Participants in these forums have used these regulations in the past to get their cable providers to stop encrypting local DTV rebroadcasts. First, make requests over the phone that they do this, carefully documenting the results and the names of the people you talked to. If they can't or won't help you, get a name and address of who you should send your complaint to. If you didn't get results over the phone (and you probably won't), pen a letter to your cable provider's management, describing your complaint and your efforts to correct the problem to that point, naming their employees that you talked to. Make it clear that you sent a copy to the proper office of the FCC (don't ask me what that is--go to
www.fcc.gov and dig it out
). I haven't done this myself, but this is what people in other forums have described doing. Locally, TWC was compliant with this from the start, but a complaint had to be made to Cox, which they eventually responded to; I can tune their local DTV rebroadcast with the 46231 sans CableCARD.