...PAYBACK! The question has to be asked, why can't all members be automatically signed up for it? Members should only have to register to collect it and decide as now what to do with it. If not collected after a reasonable period the payback could be donated to Charity or simply expire if GG decides the auto registering is too expensive.
Good news. that is how it works already Every giffgaff member on the community is automatically entered into the payback system and can start earning points instantly, either through community participation or recruiting other people by their SIM referral link or by ordering SIMs and giving them to others.
This is not an exclusive thing, it just gives newer members more of a structured guide so they can grasp the payback system easier. Everyone else will still be on the regular payback system and can earn as normal.