So, selfies good; sticks bad. But bad in theory, not fact, since many museum officials in the United States acknowledge that they have experienced few actual instances of selfie-stick use, or, in some cases, none. For the Hirshhorn, and Chicago’s Museum of Contemporary Art, which have yet to record a single sighting, the ban was a pre-emptive strike. Meanwhile, at the Tate Modern and the National Gallery in London, and the Louvre in Paris — two cities where Asian tourists, in particular, have made the selfie stick a highly visible part of the urban landscape — selfie sticks are still permitted.

The selfie stick originated with a Canadian inventor named Wayne Fromm, who took out a patent in 2005. With the arrival of Facebook, Twitter and YouTube, the stick spread like wildfire throughout Southeast Asia and beyond. In South Korea, selfie sticks became so heavily used that the government stepped in, ruling that selfie sticks with Bluetooth technology were communications devices and had to be certified. Anyone wielding an illegal stick there can be fined and jailed for up to three years. The selfie’s westward creep followed, as European and American entrepreneurs picked up on the trend.

No one knows how many selfie sticks are out there, though Andy Brennan, an analyst for the market research firm IBISWorld, has estimated that hundreds of thousands have been sold in the United States since last summer.

Noah Rasheta, whose photographic accessories company, iStabilizer, has produced 150,000 selfie sticks since 2011, said, “It’s not the product that’s at fault, it’s the behavior of the people using it.” If the museums think of the selfie as a free form of advertising, he argued, they should encourage visitors to take a better picture.

Museums have always struggled with an intrinsic conflict: how to expose their collections to the maximum number of visitors while protecting their priceless treasures. Their efforts are generally encoded in a set of guidelines, some universal — do not touch the art, do not smoke, do not bring food, do not talk on a cellphone — and some quite particular.