The National Gallery of Canada had some exciting news today. It announced a major spring and summer program featuring works by Alex Colville, Marc Chagall, and more.

Just don’t bring your selfie stick.

The hand-held, telescoping pole designed to extend your smartphone camera’s range of view is all the rage these days. Time Magazine named it one of the top 25 inventions of 2014.

But they are not welcome everywhere. The National Gallery of Canada allows photography throughout its permanent collection, but it has an existing ban on camera tripods and monopods. Director and CEO Mark Mayer says selfie sticks will fall under that ban, although he points out it hasn't been an issue. "We haven't given it any thought because we haven't seen one yet."

“They’re just too dangerous,” says Mayer.  “It’s just too easy to lose control of it and knock into a priceless painting.”

The National Gallery is not alone with its concerns. The Museum of Modern Art in New York recently announced a ban on selfie sticks. Other galleries around the world have done or are considering the same.

Selfie stick bans have also cropped up in less-obvious places. Carnival in Rio de Janeiro has implemented a ban for parade participants. Some English Premier League soccer clubs have banned them from stadiums, fearing their potential use as weapons.

But some places are OK with selfie sticks. “We welcome selfies so we have no problems with selfie sticks,” says John Swettenhan of the Canadian Museum of Nature. “We want people to have nice memories of coming to the Museum of Nature and selfies are a big part of the experience these days.”

Swettenham agrees that people using selfie sticks need to exercise some etiquette and common sense.

They shouldn’t be held too close to any of the exhibits. They shouldn’t be used in crowds. Their use shouldn’t interfere with the view or enjoyment of others.

And, while your phone is on the selfie stick, it’s best to not answer any calls.