It would be nice of the GMs could "lock out" the NPCs so that no one could send them a PM.

My PM list in some games is huge and occasionally someone links an NPC in a conversation or sends a PM to just that NPC and it sits on the bottom of the page for weeks before I notice it.

In reply to Grimmond (msg # 1):

+1

It should be an option that can be turned on or off. Sometimes I'll recruit a lurker to play a recurring NPC without telling the players.