Hey Earthdog,
Same thing happens with no firewalls. But it appears the only conversations not seen by the players not speaking to the npc are the 'non essential' ones that don't advance the plotlines much or at all and are for 'flavor' in the area.
Now that I think of it, I did have that happen in my last multi. There's a guy near the bar in CC that will hit on your female pc if she talks to him. I told the host of my other game that and he went to talk to the npc, just to see what he said. I never saw the dialog.
Cloudy
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Raindancer of the Laughing Hyenas Clan
Storm-Queen
StormCloud of the Black Knight: Heart Mind Soul Forever
"To sleep, perchance to dream..."