The correct answer is that "anyone who calls themself a 'Trekkie' is a Trekkie." It's self-identification, same as those folks who stand up in Alcoholics Anonymous meetings and identify themselves as "I'm ________ and I'm an alcoholic." Their "rule" is that no one can tell you that you are one unless you choose to so identify yourself, and if you do no one can keep you out.
Oh that's such a cop out.
Timmy walks into an AA meeting
Timmy: "hi, my name is Timmy and I am an alcoholic"
Group: "hello Timmy"
Timmy: "I tried my first beer yesterday, and I got drunk and feel asleep for the whole afternoon. I am so ashamed, mommy had to come and wake me up."
As if the group wouldnt laugh their asses off at Timmy. Especially when some of those AA members had their lives ruined, lost their families, beat their kids and spouses........