Don't know depends on what admin has in mind for requirements.
If they are plainly joining the forum for the sake of the 5$ they wont be able to make that money i guess.
Any forum would like to have members who join the forum to be with it for long time not just for earning.
Anyways all the best for that
See even I joined in GAF only for that $5, but still I'm active there because once I used to it, I started liking. Similarly, I believe out of 5 referrals, who want to join GAF for only $5, at least 3 referrals will stick with GAF once they used to the forum. In that way, it will benefit the forum.