YOu DO need to have an account to play H2H, but it does not need to be a paying account.
If you ask them to and are currently a paying customer you can have them close the account so you don't have to pay for it anymore but ask that they leave it open for H2H usage so you can retain a callsign within H2H... otherwise you can register for an account without putting in CC info and stuff but you will not be able to play anything but H2H, you will also not be able to set your handle, you will be given a NewU id.
-SW