No, you are able to get HD BROADCAST networks for free, even if they are not offered in a package. Try this experiment. Disconnect the cable box and connect the cable directly to your TV input. Perform a channel scan and see what you get. You may find some analog cable channels if they haven't all been converted yet, but you will also find the digital HD broadcast networks. Now, you won't have any guide information, but they will be there. This is considered sufficient to meet the FCC requirement.
Your confusion is regarding what comes through the cable box. The cable company is not required to map these clear-QAM channels through the box or provide guide information unless you pay for the HD box and service.
Now, you could place a splitter on the cable comoing into the set and run one cable directly to the TV and the other to the box. You would get the HD broadcast channels that way, although it would be less convenient.