By JOYCE WADLER

It’s the lore and lure of bucolic small-town living: The community is so safe, people don’t even lock their doors. But Joyce Weisshappel, a 63-year-old vice president with the Corcoran Group, a real estate company, does not live in a small town; she lives in Manhattan, in a luxury apartment building.

And she doesn’t think she has ever locked her door in the 30 years she has lived there - she doesn’t even know where the keys are.

Why would she lock the door, she asks. There are 24-hour doormen, delivery people cannot enter the building unescorted and she’s never heard of a crime being committed there.

The No Lock People: You may doubt their existence, particularly in big cities like New York, but people who do not lock the doors to their houses and apartments do exist - and in surprising numbers. A 2008 survey by State Farm Insurance of 1,000 homes across America reported that fewer than half of those surveyed always locked their front doors.

But when a committed Lock Person lives in the same building as a No Lock Person, things can heat up. “It’s the height of naivete,” says a New York businesswoman who identifies herself as a Double Lock Person. (She would not use her name, she says, for fear of incurring the anger of her neighbors.)

“I live in a high rise with a doorman, I’ve been there 15 years and I’ve never heard of a burglary in the building, but that has absolutely nothing to do with it- it’s common sense,” she says. “There is someone in my building who never locks her door. Her story is she would only lose the key. She has told the building staff to just go in.”

The building managers sent this resident a letter, Ms. Double Lock says, notifying her, “If you are stupid enough to keep the door open and yell to anyone within hearing distance that the door is open, and anyone who hears it can go on in, the building isn’t going to be responsible for it” if anything happened to her belongings.

A spokesman for the New York City Police Department reported that of the 19,263 burglaries that took place in New York City in 2009, 5,041 did not involve forced entry.

While out-of-towners may cling to the notion of New York as a city of triple locks and metal bars bracing the door - an image common in movies from the 1960s and 1970s - that idea is dramatically out of date. According to the Police Department, there were 210,703 burglaries in the city in 1980, more than 10 times as many as there were last year.

And in some ways, the city may be a victim of its own success - people may have become too comfortable, says James Murtagh, the commanding officer of the 19th Precinct on the Upper East Side of Manhattan.

“My crime prevention officer goes to visit each one of the burglary locations,” he says. “And the resident will often tell the officer, ‘I don’t lock the door,’ or they feel safe or it’s a safe neighborhood. They blatantly admit it to us. The logic to them is they feel comfortable enough to leave it open.”

But the decision to lock or not lock is not always logical - often, it is based entirely on emotion.

“A person’s perception of safety is not necessarily tied to statistics,” says Lois Braverman, the president of the Ackerman Institute for the Family in New York, which trains mental health workers. “A person’s idea of safety is tied to variables that are very illogical but are part of the story they tell themselves.”

Ms. Braverman - who lives in a Manhattan doorman building where she always locks her door, but spent much of her adult life in a house in Des Moines where she usually left her door unlocked during the day - also insists that one should not equate locking habits with personality. She knows of no data that suggest No Lock People are risk-takers, she says, and it would be incorrect to assume that those who triple-lock their homes are cautious.

“I know of people who lock their doors, but will ski down the hardest, steepest runs in Colorado in their 60s,” she says.