Cablevision wants Social Security numbers so that it can collect what it views as unpaid bills.

Online chat:

Arthur K.: Having your previous address helps us to identify that as well.
Kenneth Matinale: Why would Cablevision need my Social Security number?
Arthur K.: We use it strictly for identification purposes.
Arthur K.: We do NOT run credit checks.
Kenneth Matinale: None of my other accounts asks for Social Security number. I log in using ID and password.
Arthur K.: Once your service is set up, we would also suggest that you create an Optimum ID and password.REE/
Arthur K.: Plus, we are not asking for your Social Security number.
Arthur K.: We are only asking for your contact phone number and your previous address.
Kenneth Matinale: Again, why did Cablevision need my when I called two days ago?

Arthur K.: Kenneth, I'm sorry but I do not understand your last question.
Kenneth Matinale: My Social Security number was absolutely required by the Cablevision order taker I spoke to a couple of days ago when I tried to switch from Verizon. When I refused, I was denied service.
Arthur K.: Kenneth, I cannot speak to your earlier experience, but I do apologize for any inconvenience or unpleasant experience.
Arthur K.: Sometimes we do need a Social Security number when the phone number and previous address do not specifically identify the potential customer.
Arthur K.: In this instance, I'm fairly confident that we will be able to proceed with just your phone number and previous address.
Kenneth Matinale: The other person was polite but insisted that Social Security number was required for security reasons.

Kenneth Matinale: I concluded that Cablevision wants Social Security numbers so that it can collect what it views as unpaid bills. It certainly could not be for security.

Arthur K.: Kenneth, part of trying to identify new customers is, in fact, an attempt to identify past customers who have unpaid previous balances.
Arthur K.: We do try to collect past due balances for service we have provided.