Provide a check box to opt out of the 2 tier commission emails. We only have 1-tier plan.
We are only using a 1-tier affiliate commission program. If a new affiliate was cookied by a previous affiliate, therefore "referred" on the new affiliate's profile page, the previous affiliate gets an email from every sale the new affiliate makes, which says, "You've referred a sale and made $0 commissions. Previous affiliate is irritated and deflated even though the commission we pay for a 1-tier program far outpays what they'd make even if it were a 2-tier program.