A couple obtain a hotel room under the name of "Mr. and Mrs. Smith" or some other — usually similarly bland — pseudonym. They may be married... just not to each other.
- The Firesign Theatre subverted this on their comedy album, How Can You Be in Two Places at Once When You're Not Anywhere at All? A single person signs in to a motel as "Mr. and Mrs. John Q. Smith"
"Surely you can't believe I'm Mr. and Mrs. John Q Smith of Anytown, USA?" "Of course we do!"
- Played very much for drama in this Glee fanfic, where Kurt and Blaine first meet as adults. They meet because their respective husbands, who have had a long-term secret affair with each other, decide to go on vacation together, during which their plane crashes and they both die. Kurt and Blaine might never have found out about the cheating thing (or met each other), if their husbands hadn't pretended to be married when they bought the plane tickets. Thus, Blaine's husband is listed as Kurt's husband's husband on the passenger list, and the airline calls Kurt's dad instead of Kurt since they assume that Kurt died in the crash.
- Played with in No Way Out. While Kevin Costner and Sean Young are conducting a torrid affair, Young comments about the lameness of registering them as Mr. and Mrs. Smith. Costner says, "But I spelled it with a Y."
- Mr. & Mrs. Smith (2005): But pretending to be a married couple is what brings them together and causes them to decide to use the other person as their cover. Lampshaded later when they begin to fight, and Jane asks her assistant to look up his hotel history, the assistant asks, "Look up what, John Smith?"
- Superman II: Clark and Lois do this for their Niagara Falls expose. This doesn't help Clark, who is already sweet on Lois.
- The 39 Steps: the 1935 Alfred Hitchcock version. "You sign, darling, the sooner you get used to writing your new name the better." (Hannay prompts her with "Mr. and Mrs. Henry Hopkinson," one of many aliases beginning with H he adopts during the film.)
- Quantum of Solace "We are teachers on sabbatical..."
- The Thief: Katya and Toljan pretend to be married so they can get a room in a communal apartment in 1952 Russia.
- A Night in Casablanca (1946). When a pompous and wealthy married couple by the name of Smythe turns up demanding a suite, Groucho's character assumes this trope is in play and sends them packing.
- Referenced in an old joke, where a man signs his name with an X, hesitates and then draws a circle around it because "Sometimes a man doesn't want to use his right name!"
- Atlas Shrugged: Hank Rearden and Dagny Taggart.
- Caravan to Vaccares: In this Alistair MacLean novel, our hero, Neil Bowman, signs into a hotel. The clerk looks at the girl he is with and says, "And this is Mrs. xxxxx?", he replies, "Don't be silly," and they go to their room. Once there, she objects to his not signing them in as husband and wife, and he tells her to look at her hands. He then points out she isn't wearing a wedding ring and that clerks notice that.
- In Agatha Christie's Partners In Crime stories, the (married) Spy Couple Tommy and Tuppence Beresford frequently use aliases during their investigations - partly because it's fun, and partly to prevent High Society from discovering that they do serious work. In one story, they get into a discussion of what alias to sign a hotel registry with in front of the desk clerk, who is stunned that anyone would be so open about it.
- In M. T. Anderson's book Feed, doing this is one of Violet's dreams. Eventually she and Titus end up actually doing this for real, and it's the emotional climax of the novel when he rejects her attempts to sleep with him.
- Subverted in The Face on the Milk Carton. The two teenage characters decide to check into a motel. The girl signs her real name note — Jane Johnson — and the clerk sarcastically says, "Big imagination, lady."
- Played with in the novel The Wheel Spins (which became the Alfred Hitchcock film The Lady Vanishes): a group of English tourists includes a couple who introduce themselves as Mr and Mrs Todhunter; there's some speculation among the other tourists about whether they're really married, which is settled by the observation that if they were up to something they'd have picked a nondescript name like "Smith" or "Brown". It turns out that they aren't married to each other, and that they picked "Todhunter" because the man's name really is Mr Brown.
- Subverted in Going Too Far by Catherine Alliott. When Polly goes to the hotel where she believes she spent the night with Sam, she checks the guest book, expecting that he would have signed them in under some nondescript name; but discovers he used their (separate) real names. This turns out to have been deliberate so he could create a false alibi for burglary.
- There is a poem (told as a memoir) that mentions the speaker having to sign into a motel like this to have sex with her college boyfriend, because at the time (probably about The '50s or early in The '60s) they wouldn't be able to get the room despite being both consenting adults and/or it would have caused a scandal, and they wouldn't have been able to do it in either of their dorm rooms, like many modern college students do today.
- Amusingly Inverted by the Happily Married couple in Manalive. Their names actually are Mr. and Mrs. Smith, but they periodically reenact their courtship to keep their marriage fresh, during which times the wife uses whatever color of dress she happens to be wearing as a last name (Miss Gray, Miss Green, Miss Brown, etc.).
- In As Time Goes By, the two main characters once signed in to a hotel as Mr. and Mrs. Ambrose Smith to keep from being too obvious.
- Twin Peaks: Nadine Hurley and her teenage boyfriend Mike.
- An episode of Golden Palace has Rose trying to keep a couple who's doing this from sleeping together. After an episode of shenanigans, she finally drives them out of the hotel. The episode ends with another man checking in as "Mr. Smith". When Rose asks if there's a "Mrs. Smith", he responds that there is not, but there is a "Mr. Jones".
- In Keeping Up Appearances, Hyacinth and Richard spend a weekend at a bed and breakfast, and Hyacinth is exasperated by a loud couple in one of the rooms. Richard looks at the sign-in book, and sees the name of the couple: Mr and Mrs Smith. Turns out Mrs Smith is her sister, Rose.
- In Citizen Smith, when Wolfie Smith and Ken are trying to have a dirty weekend away with their girlfriends, Wolfie books them all into a hotel as 'Mr & Mrs Smith - twice!'
- Babylon 5: A variation occurs; this is the only way Marcus and Dr. Franklin can get fake IDs together on their way to Mars. It's Undercover as Lovers at the same time, which adds an extra layer of funny — honeymoon suite and all.
- In an episode of Smallville, Chloe Sullivan and Oliver Queen go on a weekend getaway and check in a hotel as Mr. and Mrs. Green, which not only is a common and bland last name but also refers to Oliver's other identity.
- On Living Single, Khadija meets an old fling of hers and describes how they had checked into a hotel together under some sort of bizarre name, because Smith seems too easy.
- In one episode of NCIS Tony and Ziva go undercover as a couple who are also assassins.
- In the Murdoch Mysteries episode "The Lockdown", a hotel clerk explains to Murdoch that tracking down the guests would be difficult: "We get a lot of 'Mr Smith' and 'Mrs Jones' here."
- On Midsomer Murders DCI Tom Barnaby find out his boss has been using Barnaby's identity at a hotel where he has been having an affair.
- Factors into the resolution of one murder on CSI: Miami. The murder takes place on a cruise ship. Among the suspects are a married couple, and the woman eventually is revealed to be the killer. She and her "husband" are married - just not to each other, and they sneak away once a year on a vacation to have a fling. Unfortunately, she happened to bump into the murder victim on this cruise, someone she knew from home, and she killed her acquaintance to prevent her from spilling the beans.
- On Schitt's Creek Stevie takes her Best Friend David to a spa to console him over his romantic troubles. The Amicable Exes pose as a honeymoon couple to get free booze and upgrades, but the hotel goes way overboard in fetting the "newlyweds" and this leads to much awkwardness.
- Inverted in a The Wizard of Id strip: The couple are married and named Smith, and the wife suggests using a different name because using their real name always results in snickers.
- One episode of The Goon Show features a Spanish hotel where every room is occupied by Señor and Señora Smith.
- In the webcomic The Bare Pit, two agents check in undercover as Mark and Mary Jones.
- The 1934 Merrie Melodies short "Honeymoon Hotel" (the first in color), all the hotel's insect guests sign the register with a rubber stamp reading "Smith." This cartoon was based on a Busby Berkeley Number from Footlight Parade, where Smithical Marriages were the rule:
We're the house detectives,
But we're puzzled with
The fact that no one stops here
Unless their name is Smith.
- Animaniacs: Referenced in a blink-and-you'll-miss-it verbal gag in their Disney parody short "Jokahontas," when John Smith introduces himself to Poca-Dot-as. "I'm John Smith." "Oh, I bet you tell that to all hotel clerks."