How will bitchat solve spam in the geohash mode?

Paid relays are not good for onboarding and still need moderation. Web of trust does not work with ephemeral identities. Rule-based spam filtering doesn't work: it's a cat-and-mouse game that you can't win and rules get ever more complex, with false positives.

Bluetooth mesh mode doesn't have the spam problem, because spammers don't have global reach.