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.
- 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.)
- In About Elly, Sepideh claims that Ahmad and Elly are married, as it is illegal in Iran for unmarried couples to holiday together.
- Invoked in Blue Crush: Anne Marie doesn't bother correcting the room service attendant who calls her "Mrs. Tollman" on the phone.
- Call Her Savage: When Larry Crosby dumps his girlfriend Sunny, he tells her that he caught her checking into a hotel with another man under the name "Mr. and Mrs. Smith".
- Diamonds Are Forever. James Bond and Tiffany case are checked into the bridal suite of the Whyte House under the names "Mr. and Mrs. Jones". Felix Leiter is not impressed.
- In Doctor at Large, Dr. Sparrow gives his last name as "Phillimore" when staying at the Judges Arms with Nurse McPherson. The only problem is he still signs his own surname in the book, leading Mrs. Digby to give them two separate rooms.
- In Elevator to the Gallows, Louis and his girlfriend sign the register as Mr. and Mrs. Julien Tavernier, which proves relevant late when the police focus on Julien for the murder of the Germans.
- Occurs en masse, in the "Honeymoon Hotel" number in Footlight Parade.
- In It Happened One Night, Peter and Ellie have to pretend to be married to get a room in a motel.
- In Laser Mission, Gold and Alissa check into the Swakop hotel as a married couple.
- 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?"
- 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.
- Played with in No Way Out (1987). 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."
- Outward Bound: Henry pretty much gives it away when he stammers out that Ann is "my...wife."
- Quantum of Solace: Bond and Fields check into a hotel under the cover of a married pair of teachers on sabbatical:
James Bond: [at a dirty, small motel] What are we doing?
Strawberry Fields: We're teachers on sabbatical. This fits our cover.
James Bond: No it doesn't. I'd rather stay at a morgue. Come on.
[they go to a nicer hotel]
James Bond: [to the hotel receptionist] Hello. We're teachers on sabbatical and we've just won the lottery.
- Superman II: Clark and Lois do this for their Niagara Falls expose. This doesn't help Clark, who is already sweet on Lois.
- The Thief: Katya and Toljan pretend to be married so they can get a room in a communal apartment in 1952 Russia.
- Whipsaw: Since they’re technically on the run, Vivian and McBride pretend to be married to get a hotel room.
- 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!"
- Blood on Biscayne Bay: People cared about stuff like this in 1946, which is why faithless Trophy Wife Estelle Morrison and the man she was cheating on her husband with had to register in a motel as Mr. and Mrs. D.G. Hays.
- 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.
- 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."
- In M. T. Anderson's book Feed (2002), 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 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.
- 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 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.
- 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.
- 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.
- 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.
- 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.
- Barney Miller: In "Grand Hotel" Huntsinger, head of security at a local hotel, brings in a college student who took his 17-year-old girlfriend to the hotel. Huntsinger sneers at the young man he arrested for registering the couple as "Mr. and Mrs. Smith." The young man's name? Howard Smith.
- The Brittas Empire: In "The Lies Have It", Helen went to a restaurant with a man she was having an affair with (named John Rawlinson) under the alias of "Smith". This comes in handy when this and a vague description of the duo lead a suspicious Brittas to believe that it was Michael T. Farrell III and another woman who was there instead.
- 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!'
- Columbo: In "Murder in Malibu", Wayne's sex partner returns to him the fake wedding ring they used for a tryst in a hotel.
- 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.
- CSI: NY: In "Point of No Return," a former M.E.'s wife is found dead in a seedy motel room. Arriving at the scene, Mac asks Flack if any of the other guests heard anything. As part of his summary, Flack states that "Mr. and Mrs. Smith in the room next door" had rented the place by the hour.
- Dcotor Who: In "The Crimson Horror", the Doctor and Clara encounter this issue when the Doctor tries to join Sweetville using his Go-to Alias of 'Dr. John Smith'.
"Dr. and Mrs. Smith. Oh, yes, you'll do very nicely."
- The F.B.I.: In "Pound of Flesh", Erskine and Jim track down a pair of suspects to a No-Tell Motel where they had checked in as the Smith brothers. When Jim asks "Smith?", the proprietor replies:
"Face it, honey. If it weren't for the Smiths of this world, I wouldn't have any business at all."
- 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.
- 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.
- Manhattan: Invoked by the US Army as a necessary cover identity for Charlie Isaacs and Helen Prins, who travelled to Tennessee to sign off on a breeder reactor to generate plutonium.
- On Midsomer Murders DCI Tom Barnaby finds out his boss has been using Barnaby's identity at a hotel where he has been having an affair.
- 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."
- Perry Mason (2020): The hotel clerk who delivers devastating testimony in "Chapter 6" reveals that George Gannon checked himself and Emily into the hotel as "Mr. and Mrs. Stanley Kelly."
- 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.
- 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.
- 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.
- 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."
- Harley Quinn (2019): In "Harlivy", Harley and Ivy check into a resort under Mrs. and Mrs. Gordon, billing the entire thing to Jim Gordon's credit card that they scammed out of him.
- 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.