If the group uses an inactivity setting, then members will get a message five days before they are bumped from the group because it's a cm system message. Inactivity in this case means the member hasn't clicked into the group in the set period of time 30-180 days.
If a member is deleted from a group by admin, then it's likely she wouldn't get a message because it would be up to the person deleting to send it. If you can't find the group at all then it is possible that the owner asked to have the group disbanded. If it has under a certain number of members the cafemom will, at the request of the group owner, delete a group. Your best bet would be to message the group owner directly. If she isn't on your friends list, you put her name in the search field at the top of the page and then click into her profile from the search results.
at 3:39 AM on Mar. 29, 2009