Is member A,B,C a member of any other groups that may have permission? The only way I know would be in the member management section and double check that the member is not in any other groups than Trouble Makers.
Oh while you are editing the member make sure they are not a moderator,Global Moderator or Admin.

Last edited by Ruben Rocha; 11/20/2008 3:40 PM. Reason: forgot something

Blue Man Group
There is no such thing as stupid questions. Just stupid answers