Re: *WHO* is authorized to dispose of a flag?
There are no legal restrictions on disposal of American flags -- anyone can do it. Military regulations, and the civilian flag code, just say that it should be done in a dignified way. The military also specifies that the disposition will be done in private; the civilian code said that originally but no longer does.
"We live by symbols, and what shall be symbolized by any image of the sight depends upon the mind of him who sees it."
-- Oliver Wendell Holmes, Jr.