Ever had a session where you stayed on an hour longer than you wanted to because of a good ranking group or cabal raid/retrieve dynamics? If you have, you'll notice that as soon as one person leaves, two, three, sometimes even more all leave at about the same time.

Now, some people see this and say "Ahah---cheaters!". I see it and just figure a bunch of people stayed on past when they need to log off, and as soon as one or two leave, the snowball starts rolling and everybody logs off.

I figure it's the same way with imms. Nobody plays forever, everyone has a life, some have families, etc. We all grow up eventually, even if your over the hill like me. For whatever the original reason, when an imm leaves, a few others are going to "reassess" their situation, level of enjoyment, free time to commit to cf, etc. Some of those others will decide it's time to move on as well.

In fact, I'd have to say that most immortal departures occur in fits and spurts and it's somewhat normal.