The GITMO GAG I wonder if this policy was in place at Buchenwald? According to USA Today:

Military and civilian employees at the U.S. prison for suspected terrorists at Guantanamo Bay, Cuba, were warned recently not to talk with attorneys who represent detainees held there, according to a document prepared by the legal office of the Army-led task force that runs the facility. The document, obtained by USA TODAY, says that soldiers and interrogators are not required to give defense attorneys statements about the "personal treatment of detainees" or any "failure to report actions of others." It also says that refusing to cooperate with defense attorneys "will not impact your career."

There is nothing per se wrong with telling anyone "you don't HAVE to talk" but its another to flat out encourage stonewalling. Unless of course, you are a member or supporter of the Bush Administration.