guess I was wrong
both retired regular military officers and enlisted are subject to all provisions of the UCMJ by virtue of the language in Articles 2 and 3. As a practical matter though, the military services rarely exercise that jurisdiction. It is entirely within the Service Secretary's discretion. You can read a very good and comprehensive legal discussion of this issue by going to: http://www.loc.gov/rr/frd/Military_Law/Military_Law_Review/pdf-files/175-03-2003.pdf It will be the first article in the journal.
Read more: Does Art. 88 UCMJ apply to retired military officers and enlisted - JustAnswer
http://www.justanswer.com/military-law/6zbzz-does-art-88-ucmj-apply-retired-military-officers-enlisted.html#ixzz2Cu0bEI26
Retired members of the uniformed services who are entitled to retirement pay are also subject to the UCMJ, as are retired reservists who are receiving hospital care in the VA system
http://en.wikipedia.org/wiki/Uniform_Code_of_Military_Justice
This may only apply to Commisioned Officers
ART 88
“Any
commissioned officer who uses contemptuous words against the President, the Vice President, Congress, the Secretary of Defense, the Secretary of a military department, the Secretary of Transportation, or the Governor or legislature of any State, Territory, Commonwealth, or possession in which he is on duty or present shall be punished as a court-martial may direct.”