Breaking encryption is a violation of federal law and the terms and conditions of the the rental. It is not appropriate to advocate illegal activity in online discussions.
If you record the analog downconvert, you are only violating the terms and conditions of the the rental, which is still wrong, but not a direct violation of federal law. However, you do get a substantially inferior video than the HD you get when watching the movie on the cable box itself.
The On Demand service is for watching programming as it is broadcast to you, when you order it. What you are supposed to do, if you want to be able to watch the movie at your leisure, is purchase a copy of the video disc. Please use that approach.