True. Then the only option is to somehow restrict relay write access, which is not great. Bluetooth mesh works better because spammers dont have global reach.
Discussion
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.