I had that happen to me; I had to activate a new credit card, one which I don't use, but since I recently consolidated some debt, and closed some accounts, I figured I would at least activate it, and keep it in the drawer, so if i need it, it's ready to go.
So i call, and after entering my number, etc. i am transferred to a live person. Who goes over their credit protection plan, and then says, "so i'll sign you up and you can cancel within so many days" - I had not had a chance to either refuse or accept, and i immedaitely said, very firmly, No, do not sign me up, I DON'T want it. But had I not been listening carefully, I'm betting I would have been paying for some service i neither want or need!