Currently mirc only uses the extended LIST syntax (like LIST *mirc* or LIST >50) if the server is running an ircd known to support it. So on more obscure, lesser known ircds such as austhex (run on AustNet), mirc uses a full LIST even though the server may support the extended syntax. I think it should always send it, and if the server returns an empty list, then use the old fashioned way of full LIST and filtering out unwanted channels.

Why?

why? DO YOU ASK WHY???
lets suppose you are in one server that have more than 30000 channels (and we know that at least 10000 just have 1 or 2 people on them)
now, lets suppose that you accidentaly sent /list
ok, you are dead
if you do a /list *lol*, you are dead again
if you want to live, you have to make a /quote list *lol*
got it?

Oh I see I misunderstood the post.
So mIRC has no real way of determining if the ircd supports extended list?
If this is the case I agree.