A character is reluctant to give out a particular bit of information (no matter how important) because the way they acquired that knowledge is an Old Shame, revealing of their criminal lifestyle or otherwise distasteful.
See also ...Or So I Heard, I Read It for the Articles, Morton's Fork, and Big Secret. Compare Unbelievable Source Plot, where they want to share their knowledge but can't; Closet Geek, where the social stigma of having nerdy interests is shameful; and I Never Said It Was Poison, where a character accidentally implicates themselves in a crime by revealing too much information.
- A commercial for a fast-acting bandage features a guy putting them on some fingernail scratches on his back after visiting his mistress. He goes home, hugs his wife... and notices she has the same bandages in the same spot.
- One Buck Danny story has him compete against a foreign pilot. The pilot, knowing Danny's plane has been sabotaged, challenges Buck to an acrobatics duel, adding a condition in which both pilots will prove their skill by repeating the previous pilot's figures and add one of his own (the stress quickly destroying Buck's plane). Buck accepts, then adds a condition of his own: that they prove their skill by operating on unfamiliar machines by switching planes (having learned of his plane's sabotage). The foreign pilot quickly backs down.
- The Sting. Doyle Lonnegan tries to cheat Henry Gondorff with a stacked deck during a poker game, but Gondorff outsmarts him by switching out the cards he was given for better ones.
Floyd: We can't let him get away with that.
Lonnegan: What was I supposed to do? Call him for cheating better than me in front of the others?
- Legally Blonde: Brooke Windham's lawyers beg Brooke for an alibi to save her from going to jail for her husband's murder. It turns out she has one— she was getting a liposuction, and as fitness mogul, such knowledge would ruin her reputation. Elle agrees to keep this a secret.
- In The Dresden Files, it is eventually revealed Bob knows how to kill immortals. The reason he's in hiding is that if he goes spilling the beans the powers that be will actively hunt him down rather than just tolerate his continued exile. Making this more of a Fearful Source of Knowledge.
- A straighter example would be Bob's source of necromancy knowledge.
- Played for Laughs in Animorphs where Rachel offhandedly mentions what kind of volcano they're looking at. After some questioning as to why she knows, she defensively tells them it was on the The Magic School Bus. Gets a Call-Back later on when nobody questions a piece of information, since they'd all seen the The Magic School Bus on that subject as well.
- Played for Drama in Judge Dee. The judge is facing a crime that he cannot prove (examinations of the body show no poison and no wounds), so a young woman tells him offhandedly about wives married to abusive husbands, sitting in their rooms repairing their shoes with a hammer and tiny nails, and how easy it is to drive the nail into the skull of a sleeping man... The judge has the body reexamined, finds the nail, and has the victim's wife arrested. The young woman who told him commits suicide to prevent the judge agonizing between his conscience and his duty (she admitted to murdering her husband in front of him, but had every reason to).
- Miriam Allen deFord's short story "Walking Alone". A man calls into work and lies, saying he can't come in that day due to his bad back. He then goes out to the country for a walk. While there he sees a young girl being kidnapped. He decides not to call the police about it since his boss would find out about his lie and fire him. The girl's body is found and a man is accused of the murder. The protagonist knows that it's the wrong man since he saw the real one, but he still doesn't come forward. The falsely accused man is tried, convicted and executed for the crime, and the protagonist goes mad with guilt.
- In PartnerShip, the five Royal Brats that Nancia ferried to their remote postings in the Nyota system are all planning to use their positions for various kinds of corrupt practices (they even have a bet going; the one who makes the most shady money in five years gets a cut of the others' operations). However, Nancia can't tell anyone about it because she got the information by refusing to introduce herself and letting them think they were aboard a mindless drone, which is considered tantamount to spying.
- In O. Henry's story "A Retrieved Reformation", a reformed safecracker who had settled down under a new identity uses his old skills in order to save a child trapped in a safe.
- The Judge Dee Fan Sequel "The Chinese judge's survival guide" sees the judge looking for the head of a vast conspiracy to send troublemakers and criminals to an out-of-the-way town when a shopkeeper reports Tao Gan's shoplifting to the local judge. This turns out to be a mistake, since Dee deduces that if the shopkeeper caught Tao (a very good thief), he must be a professional himself. And if he can go and report it without caring that this automatically marks him as a criminal as well, then there is a very good chance the man he's looking for is in the town. He's right.
- One of Roald Dahl's stories has a woman cheating on her husband with a richer man. One day, the man ends the affair, but he sends her a magnificent fur coat as a gift. Unsure of how to plausibly bring it home, she hits on the idea of dropping it in a pawn shop, then telling her husband she found the ticket. For extra safety, she has the husband exchange the ticket. That evening the husband gives his wife a cheap fur stole, claiming it's what the ticket was exchanged for. She then sees her husband with his Sexy Secretary... wearing the coat.
- Isaac Asimov's "Hostess": Dr Tholan found the cause for an epidemic on his world, but his method of collecting evidence would be considered Nazi-like for his species. Therefore, he came to Earth in search of further evidence that wouldn't be considered unethical.
- Several episodes of Midsomer Murders have characters not reveal information that could have prevented someone's death, as this would also force them to reveal that they're cheating on their spouse or involved in shady deals with other inhabitants of Midsomer.
- In the Star Trek: Deep Space Nine episode "Dax", the Dax symbiote in Jadzia Dax's body is placed on trial for the crimes of treason and the murder of General Ardelon Tandro by the man's son. One of the symbiote's previous hosts, Curzon Dax, is the only person who could have committed the crime but didn't have a suitable alibi. General Tandro's widow Enina is incredibly reluctant to involve herself in the trial, but eventually provides Dax with an alibi - she was having an affair with Curzon Dax, and he was in her bed at the time when the crime took place. A desire to preserve Enina's reputation is also the reason Dax refused to use the alibi herself. There's another layer as well; Enina also knows the real truth of how General Tandro died, which she confesses to Dax- he attempted to sell out his own people to the rebels and they killed him for it, but this truth remains hidden to preserve Tandro's image as a inspirational war hero.
- M*A*S*H. In "Tea and Empathy", a passing soldier confesses to Father Mulcahy that he was involved with the Black Market, and reveals that stolen penicillin is kept under an old bell in a burned-out school house. As it turns out, the 4077th is having a dire penicillin shortage and can't obtain any new supplies, leaving Mulcahy conflicted about what he should do about what he knows about the whereabouts of some penicillin. He ultimately decides to go to the school house and steal back the stolen penicillin, and then has to dodge questions from Colonel Potter about the fact that the cases of drugs he brought back have the same markings as some cases that had just been stolen from the 4077th.
- Inverted on an episode of CSI: Crime Scene Investigation which is set over the course of a year. A junkie who Nick helps out at the beginning (and slowly sorts himself out over the course of the episode) recognises the smell of some drugs the murderer poisoned the victim with. However, he isn't willing to reveal what he knows until after he's gone clean, since he didn't think he'd be believed.
- Saturday Night Live: From a Weekend Update segment on January 25, 2014:
- The Garth Brooks song "The Night Will Only Know" is about a couple cheating on their respective spouses who witness a murder at a Make-Out Point and can't tell due to revealing their affair.
- "Long Black Veil": the Wrongly Accused person's only alibi is adultery, so neither he nor she tells the court about it.
- Similar in the Gary Moore song "Over the Hills and Far Away", whose protagonist goes to prison for a robbery he didn't commit because he cheated with his best friend's wife that night.
- In the dark humor RPG Paranoia you are tasked with rooting out the commie mutant traitors within Alpha Complex. The thing is, you are a commie mutant traitor yourself (as is everyone else). Naturally, knowing anything about traitorous activities, even what they are, makes you a prime suspect for being a traitor.
- The RPG version of Legend of the Five Rings includes several skills that are classified as "Low Skills" such as Forgery, Sleight of Hand, and Temptation, which if you ever exhibit or imply knowledge of, will lead to dishonor. There are, however, exceptions (for example, if you're among the Crab Clan, Shadowlands Lore is not considered dishonorable to know—because only an idiot wouldn't study the Shadowlands when you live on their goddamn border).
- A major plot point in The Elder Scrolls V: Skyrim's College of Winterhold questline is the need to recover the Staff of Magnus. Although he won't tell you directly, it turns out the College's Arch-Mage, Savos Aren, knows exactly where the staff is - he once led an expedition into the dungeon of Labyrinthian trying to find it. Two of his friends were killed as they descended into the dungeon, and when the expedition awoke Morokei, an evil Dragon Priest, Savos was forced to lock two others in the dungeon to prevent Morokei from escaping.
- Knights of the Old Republic II Atton Rand tries to explain away how he knows so much about Jedi and hand-to-hand fighting. Get enough influence with him, and he spills the beans - he was a Jedi-hunter for the Empire after betraying the Republic Army. After one of his victims showed him he was Force Sensitive and therefore a good candidate for ending up on the other side of the torture rack, he changed his name and ran away, trying to pass himself off as a low-rent smuggler.
- Arcade Gannon from Fallout: New Vegas will occasionally display a surprising level of knowledge on certain obscure topics, such as vertibirds or the top-secret SEMELE research project, but will always backpedal and deflect the question if asked how he knows so much. Gain his trust and he'll reveal where his knowledge of these things comes from - his parents were Punch Clock Villains and members of the Enclave, a nazi-esque faction that wants to restore the old American government by committing genocide against the Wasteland's inhabitants.
- The Order of the Stick:
- Vaarsuvius learned how to defeat Laurin while bound and gagged in hell. The reason for it was that Vaarsuvius's own soul had once been "rented" to three fiends.
- Played for Laughs in an early strip, in which Haley convinces the party they can trust some teenage goblins who are rebelling against their race's Always Chaotic Evil culture. When Elan asks her how she understands the teenage mindset so well, a flashback panel shows 15 year old Haley dressed as a Goth and arguing with her father, before Haley deflects the question with a sheepish "...no reason."
- Questionable Content: Marten's mother is a BDSM fetish model, but was apparently good, at keeping her job and family separate, enough that Marten didn't get teased about it. Presumably, none of the kids' parents were going to say anything on the subject either.
- One episode of The Simpsons has Bart playing truant from school and sneaking into a party for Mayor Quimby's Jerkass nephew Freddy, during which Bart witnesses one of the waiters having a string of incredibly clumsy accidents, and Freddy is arrested after being accused of beating the waiter up. Bart is then faced with a moral dilemma between letting an innocent man go to jail and testifying on his behalf, giving the school proof that he skipped school.