Q:

Contacts unexpectedly added to group

We have about 2800+ contacts in CiviCRM, including our 16 Board members. I have a "Board Members" group (access control group) for just those Board members. I also have a mail group set up for the same members. For some reason, unrelated to any action on my part as far as I can see, I am getting our entire list of contacts added to the Board Group.
I can even go in and remove all of the contacts from the Board Group, add the contacts from the Board email group back in and verify the correct contacts are in the Board Group. If I go away for some short period of time and return to look at the Board Group, all 2800+ contacts have been put back in.
Needless to say, this is annoying and we don't really need 2800 people on the Board. Does anyone have an idea what's going on and how to put a stop to it?
Thanks

A:

I can think of three reasons why this would happen.

"Board Members" is a smart group.  You can check this by going to Contacts menu » Manage Groups.  If it's a smart group, it either a) shouldn't be, or b) the criteria need to be changed.
The Board Member group is the parent of some other group. I did this by accident myself recently; you'll need to remove the parent-child link.
Some custom magic.  If you're the only administrator of the database, we can rule this out.  However, I perform similar tasks all the time, either using a) cron with a SQL query, b) the SQL Tasks extension, c) a custom extension. 

