RJMS and I were discussing this earlier in this channel. I believe you have to actually make some sort of server side change. E.g. create or edit a transaction, search, etc. every however often, not just logging in. At least that's how the auto-deleter works for demo accounts, and I assume they just applied the same process to RPs. They really did do a terrible job wording their purge warning notices though, if I'm correct about how it works.