While it is second nature for most to lock their doors as they leave the house, some homeowners throughout the country, including Manhattan, don’t even know where their keys are. Joyce Weisshappel, a vice president at the Corcoran Group, said she doesn’t think she has locked her door once in the 30 years she has lived in a luxury doorman building in Manhattan. She cites a 24-hour doorman, the fact that delivery people cannot enter the building unescorted, and that she’s never heard of a crime being committed in the building as reasons why she brazenly leaves her doors unlocked. But, while burglaries are down in New York City from the 1980s, some still occur, even on the Upper East Side. Inspector James Murtagh, the commanding officer of the Upper East Side’s 19th Precinct, estimated that 25 percent of burglaries are a result of a carelessly open door or window. “The resident will often tell the officer, ‘I don’t lock the door,’ or they feel safe or it’s a safe neighborhood,’” he said.