[smooth-c]

Maximum Stored Messages:If you set this to 0 users from this usergroup will not be able to use private messaging.

Can Use Message Tracking
Yes No

Can Deny Private Message Read Receipt Request
Yes No

Can send PMs to users who have reached their quota
Yes No

Maximum Recipients to Send PMs at a timeo not set this too high for performance reasons (set to 0 to allow unlimited recipients)

Message Throttle QuantityThis limits the amount of messages the user can send within the Throttle Check Period

These are the only usergroup options I see for banned users?

Shame there's not two perms such as "Allowed to receive Private Messages" + "Allowed to send Private Messages"