I'll tell the story from my side (being one of the 4 Co-Leaders (dumbest idea ever) of Omni) If you saw Klepto's line up compaired to ours that would explain most of it, sure we had a lot of FTW players, but we also had a lot of randoms that we picked up from ingame recruiting, forums, and so on.
Now to the actual fall.
I wasn't online for any of it which really sucks, because my ex (we're still close) calls me, bawling, talking about how she's going to kill herself and how no one cares about her anymore, so I get in my car and start the 2 hour drive to go see her, as i leave i get the text "We're getting massed get online" I do my best to send defense from my phone, but as I didn't have hacks or the ability to do any organizing while driving (over the speed limit as i was afraid she really would kill herself) I wasn't much help. Also the first wave they sent as most of us were out attacking CU, so our only real option was Retal, which went *okay* but not really anything great. They non stop waved us with (what looked like 20 players to me) for the entire day and then about 15 players all night and then 20 all through the next day, we were not prepared and as soon as people started losing land they stopped showing up to defend, there was very little oranization, so people would all just real one place because they didn't want to lose troops, leaving everyone else to lose land. basically after the first person left, everyone just followed, by the time i got home from my Ex's we were 11/20 and had lost 40k land
So I'm not sure exactly what happened, other than great timing, and very poor/little/no organization on our part.