Sorry, but they set their signaling mechanisms so that that signal is worthless. How many people who don't cancel want to signal they are going to be a future customer, as opposed to it being an accident? How many people who do cancel do it to signal they don't want to be a customer, and not because they don't want to be automatically billed? I believe the answer for both is "not many".

I think the companies do it because it benefits them, and because they can.