I noticed that it is possible to nullify everyone else's referral links without depositing BTC. I think this could become a problem if it already hasn't.
If referrals would only expire once BTC are deposited, it might keep everyone a little bit more honest.
I think it would be kind of cheap if your account said it had a 10% and then right as you're about to deposit some BTC it's 5%.
Yeah, there's a problem that occurs when it basically becomes an (unknown) race as to who can deposit and get their BTC confirmed first. And what happens if two accounts that register with that referral both have their deposits confirmed at the same time? Perhaps you can just keep the existing one-account-per-referral scheme, but have the referral link reactivate and the registered (empty) account deleted after 5 or so days of no deposits?