Participation in a cabal group is at the discretion of the gods. While it is possible for the gods to reconsider an individual's membership in a group, and it does happen, it's not common for an individual to be singularly dropped from a group. The few times I've seen it happen have been when someone is repeatedly "talked to" about abusing a privilege of his cabal group, or has explicitly stated that (s)he doesn't desire that responsibility anymore. It's not always a bad thing, it's just a change.
Recently the gods asked the janitors collectively to reaffirm their individual desires to participate. Those who didn't express an interest in continuing have been freed of their obligation and duty. This was partially motivated by a need to know who we really have, and who is just 'on the list' but essentially inactive, or worse, active but not reading the memos. The gods simply wanted to ensure a more consistent application of site policy.