Hmm this reminds me @neil we probably need absolute minimums on posts read and topics viewed, otherwise a Discourse with only, say, 20 total topics would make TL3 awfully easy to get.
Maybe set TL3 absolute minimums at 200 total topics, and 500 total posts? As in “site must have this much content to even support anyone getting to TL3?” don’t even bother processing any TL3 events at all until the site has at least that much content.