I can't think of one unless there's some kind of badly written IRCD playing a part.
That is precisely what the rest of the thread has illustrated. UnrealIRCd has a /shun ability which apparently means the server ignores all commands from a particular client, effectively trapping them on the network. So, if you've been shunned, /part is ignored. So the way I see it is, certain people want to prevent shunned users from closing their windows. Need I say more?
Regards,
