Of course there's a way! You rent a cable box from the cable company.
Somewhere on this site there's a thread from about three years ago that discusses a problem a lady had with the cable company. I believe her problem went as far up as the state attorney general. And SHE was the one in trouble, although it was not her fault.
She had ordered cable internet and the installers accidentally let a cable TV signal into her house. There was a later SNAFU and they didn't fix it, that is, disconnect her. Even though it was not her fault, and she wasn't even watching the cable, she was cited for theft of service. And hounded. And almost put in jail. I don't remember the details except that there are laws that can put a person in jail for doing what you asking us about. This happened to a lady by accident, and you are asking how to put yourself in the same situation by your own doing.
It's not an odd situation, actually. The cable company doesn't have the money to send out a truck to disconnect everyone the moment they cancel. They audit their connections by some kind of pattern, and they will eventually disconnect you. Whether you are fined or charged depends on how innocent you look. Some kind of digital decoder would make you look really really liable. You still don't HAVE cable service even though it is present in your house. If I were you, I'd watch what I could watch as long as you can and just shut up about it. Actually, that's not true. If I were you I'd get satellite or sign up with the cable company again.
A good answer is easier with a clear question giving the make and model of everything. "The biggest problem in communication is the illusion that it has taken place." -- G. “Bernie” Shaw