That would be harassment wouldn't it? Where between continual and once a day or once a month does it change from harassment to OK? How many times can I forward your number to new callers? What efforts to conceal my identity as a caller are OK?
Telemarketing, the way that it has been done in the past ten years or so, IS HARASSMENT.
Then don't sign up for phone service, it's not an entitlement.
American industry never seems to learn this basic lesson: either regulate yourself, or government will end up doing it for you. The second alternative always ends up being worse for the industry (lawyers and doctors are smart- they've always been very good at regulating their own professions).