If you post your E-junkie affiliate sign-up link, anyone can click that link to join and participate in your affiliate program near-instantly without any action required of you. We have no way (at our end at least) to present an agreement or make affiliates apply to join your program, subject to your approval.
You could still do something like that entirely from your end, having affiliates agree to your terms and apply to join from your own Web site, and only upon your approval would you give them your actual E-junkie sign-up link. Simpler yet, you could simply have an affiliate agreement page on your site, where the sign-up link at the bottom of the agreement says something like "Accept" or "I Agree". In this case, you would also want to go into your Seller Admin > Affiliate Program Settings screen and UNcheck "List affiliate program in E-junkie Marketplace".
Just in case you haven't seen it yet, we have a help page for our affiliate system here:
...and another help page for affiliates, explaining how the system works from their perspective here: