Niximus
Brownlow Medallist
This is why in 2015, i don't have any issue with them referring to us as a customer.
Even if you no longer consider yourself a member, 'customer' is still not the most appropriate description.
A fan, or a supporter better describes the relationship with the club. You need never pay a cent to be a supporter, and you can be a supporter regardless of your voting rights.
You list the Red Sox on your other teams. Now, this may not be the case for you, but I'd bet that the majority of Australians who identify as Red Sox fans have never spent any money with them.
I know a few Holden fans who have never actually bought a Holden.
A supporter or fan has an emotional connection to a team or sportsperson, and has a desire to see them succeed.