A few years ago had a couple friends that got jailed then 3 day banned and the other was warned for killing charmed people at Tiamat. They told the GM they were doing it because they were being attacked by other players, the GM didn't buy it. But the real reason they were doing it because they didn't like the LS that was killing Tiamat and thought it was hilarious when they were killing their charmed players.

So I guess it really depends on the GM you get. A lot of these NA GMs are outsourced and hired by a 3rd party company by SE anyway and know little about FFXI.

But if your bad enough to get charmed by a corse at Tiamat then you deserve to die. But why have mobs even charm players if someone can just call a GM on you for killing the charmed players?