I believe the "technical" term for taking something that does not belong to you, or something that you have not paid for is STEALING. Since you are not paying for TV service, you should not be taking the TV signal, even if it is "just sitting there". If you want local HD without paying for it, get an antenna.
Cablevision in NYC received an exemption from the FCC to encrypt even the local HD channels because people were STEALING cable. Normally, local HD channels are not encrypted, but normally people don't take what does not belong to them, or what they have not paid for, except for what appears to be a common thing in major metropolitan areas.
Chances are that Cablevision does not encrypt local HD out on Long Island, but nothing is guaranteed, since you have not paid for it, and Cablevision has no contractual obligation to provide those channels.
Verizon FiOS does not encrypt local HD, but transmits it in unencrypted Clear QAM, which only a handful of TV's are capable of receiving straight out of the box.
6 TV's in the house on FiOS and we only pay $4.99/month to connect them all!!! Power to the CableCard and WMC7!!!