In 1957 the FBI felt threatened by the Usual Gang of Idiots at MAD after the magazine ran a piece about draft dodging as a game, which involved writing to FBI Director J. Edgar Hoover and asking him for "full-fledged draft dodger" membership card. An FBI agent directed his bureau's New York offices to "make contact" with MAD and "advise them of our displeasure" and to make sure "that there be no repetition of such misuse of the Director's name." The agent also decided it was important to give his opinion on the quality of the article: "It is also of interest to note that…it is rather unfunny."
Mental Floss has the story:
Less than a week later, the Feds entered the hallowed hallways patrolled by Alfred E. Neuman. Their New York office would later report to Hoover directly that they had met with John Putnam, the magazine's art director. (Conveniently, Gaines was not in that day.) Putnam told the agents he regretted the magazine using Hoover's name and that nothing malicious was intended:
Putnam said that the use of the membership card and the name and address of the Director at the end of the game was referred to in their business as a 'gag' or 'kicker' in the same way that a comedian like Bob Hope or Milton Berle might use it.
Putnam swore that MAD would never again take Hoover's name in vain; Gaines sent off a letter of sincere apology to the Director.