My first, "For the Alliance" was put together by a 60th level Paladin, who wanted level 70+, but would take anyone.
Needless to say, it was not pretty.
With minimal resistance in Ogrimmar, the raid wiped twice.
Buffs took place in front of lowbies right in the newbie zones, so they had lots of advance warning.
Even with zero resistance in Thunder Bluff, the raid could not take out Caern, which is rather sad.

Second raid was lead by alts from Pirate, which is one of the top alliance guilds on the server, as far as PvE progression goes.
The requirement was level 80 only.
They buffed and summoned out of site of the cities, so they were hit without warning.
Four for four, with a few deaths here or there, but 90%+ of the raid alive with each city leader down.
Able to rez right there, and such.

An organized raid is worth 100x as much as a non-organized raid.
Both were Pugs.