The Trouble is Not in Your Set - S6-E14
Trivia: Marion Ross guest stars as a woman who watches a lot of TV, but believes the characters are real people. In one scene she references the following show by naming people/characters: Oprah, Donahue, The Tonight Show with Johnny Carson, The Cosby Show, Dynasty, M.A.S.H., Dallas, Leave it to Beaver. The last character she names is "The Fonz", from Happy Days, which Ross also starred in as Mrs. Cunningham.
Trivia: When Eddie is unsure of the year, Harry says, "it's 1985. Reagan is President." Eddie replies, "the actor?" This is the same response Doc Brown gave Marty McFly in "Back to the Future" when he asks Marty who the President in 1985 was. This episode aired less than 5 months after "Back to the Future" was released.
Trivia: In this episode, the rock star Eddie Devon is played by Michael Ross. Ross was the real-life husband of Markie Post, who plays Christine Sullivan.
Trivia: John McIntire and Jeanette Nolan play husband and wife and Dan's Parents. In real life, McIntire and Nolan were married to each other.
Trivia: While there have been many actors on the show over the years who played multiple characters, the character of Mrs. Smith is particularly interesting. She's an elderly woman brought in on prostitution charges, and at the end, it's implied Dan might take her up on her offer for sex. Mrs. Smith was played by Jeanette Nolan, who had previously appeared on the show as Dan's mother.
Answer: It's possible when Harry called the military, he implied that the book contained sensitive information, seeing as how many government and military officials were part of the client list.
I thought it was because he developed feelings for the madam and couldn't bring himself to turn her in.