NEW YORK — Since Melina Barker’s home in Harrison, N.Y., was burglarized about five years ago, she is hesitant to open her door to solicitors.

“Anyone knocking at my door — especially after dark, which is pretty early in the winter — makes me uncomfortable and afraid,” Barker said. Not that it’s much of an issue: During her eight years living in the town, she has been visited by only about six door-to-door salespeople.

Still, such concerns — as well as the annoyance factor — are prompting dozens of towns across the nation to adopt “Do Not Knock” registries, the door-to-door equivalent of the “Do Not Call” list. Charitable, religious and political groups are exempt, but those who knock where they shouldn’t face a summons and a fine.

Registries are a popular option for municipalities because laws that outright ban door-to-door soliciting have been overturned on constitutional grounds when challenged in court.

Communities have responded over the years by charging licensing fees to solicitors and running background checks on applicants — several states, such as Utah and Massachusetts, require statewide checks. Rye, N.Y., next door to Harrison and with a population of 17,000, was the first community in the area to adopt a “Do Not Knock” registry in 2010. Now 488 homes are listed on it.

But given the state of the door-to-door sales industry, are such precautions even necessary? Direct sales, including door-to-door sales, represented $28.6 billion in 2010, down from $32.18 in 2006, according to the Direct Sellers Association. The U.S. Department of Labor says that in 2010 there were fewer than 7,000 door-to-door salespeople, down from about 33,000 in 2000. And for all the talk of a Do Not Knock registry in Harrison, the town only issued 11 door-to-door selling permits in 2011, and had issued four permits for 2012 by May 2012.

Between the rise of the Internet and two-income couples, Do Not Knock initiatives seem to be a quaint answer to a rapidly disappearing problem.

Encyclopedia Britannica Inc., which published its first multivolume set in 1768 and was sold door-to-door for decades, announced in March that its 2010 print edition would be its last. “The end of the print set is something we’ve foreseen for some time,” said company president Jorge Cauz in a press release announcing the move to all-digital.

Even in its heyday, the door-to-door trade was hardly loved. In 1931, founder Alfred C. Fuller challenged a city ordinance in Green River, Wyo., that prohibited door-to-door solicitation. In 1937, the U.S. Supreme Court dismissed his appeal “for want of a federal question.”

It takes a special kind of mind-set to go into door-to-door sales. John Nelson, vice president of the National Field Selling Association, a trade group, spent 28 years on the road. Today, he manages a team that sells chemical products “on the ground,” as he calls it. He blames the bad rap plaguing door-to-door salespeople on the stereotype of dishonest rainmaker pitches and “snake oil” products. “There’s good and bad everywhere, but when it comes to your door in the form of selling a product, a lot of people don’t have anywhere to turn or know what to believe,” Nelson said.

Nelson said his organization, founded in 1987, has members who live up to a pledged ethical code in their relationship to both prospective buyers and would-be employees. “Prospective sales persons shall be informed of the nature and extent to which travel is involved,” the code reads, “including the method used to transport persons to and from the geographic locations where sales are conducted.”