Current rule: Only owners can ban indefinitely.
Rework suggestion: Mods can also ban indefinitely, but they have to report it to an owner within one hour of the ban, or else their mod gets removed. If the ban was valid, everyone moves on. If it wasn't, the banned user gets unbanned and the mod gets a strike. If the mod gets three strikes, their mod gets removed.
Purpose: Sometimes, bad users who deserve a permaban are around without the owners noticing it. So the mods quickly have to take action, but with the confirmation of the owners, nobody gets unfairly permabanned.