no im not going to sign up by phone just ask what their policy is, and if they say only military ill ask them why u can sign up online
They no longer restrict all of their products to members of the military and their families, as of a couple years ago they opened up certain products, including banking, to everybody. Hence during the account sign-up process, it asks if you are a military member or family member, and if you answer 'No' it still lets you open an account! Rental Car benefits are another one which is open to all members, even non-military, which is why, once you're logged into your non-military banking account, the codes will show up on their rental benefits page.
Car insurance (at very good rates, I may add) is a benefit which is only available to those who serve(d) and their families, which is why if you try to sign up for it from a 'non-military' USAA account, it won't work.