If they do something like this, it shows such complete lack of confidence in their product. "The only reason why people would continue to use this product is... if we make it sufficiently difficult to cancel". When signing up for a product, if it uses tactics like this, I assume the product is no good, and even the producers of the product know it...
I work at a non-profit and we collect recurring payments from people who don't actually get anything tangible in return. The membership are rigidly ethical in all their fundraising and messaging, but they think of "call to cancel" as being a fair practice.