Normally if you get internet-only from a cable company, they charge you more because you don't have TV service. They have a lifeline cable service which is broadcast only (and clear QAM). Getting that lifeline service +internet is usually the same cost as internet-only. So.... if your bill from teh cable company won't go up by adding the lifeline service, you could do that and not feel any guilt at all. AND have another option for TV.
I THINK that the QAM channels are in the same range as the cable internet so they can't really trap it at the pole. It *might* be seen as passive theft if you watch TV from cable, but you ARE paying for a cable service to your house. The fact that they haven't trapped out video is not your problem. I'm not sure they CAN trap all video if you have internet through them.