On a cool, Manhattan night, DJ Walton, who helps manage Alicia Keys, steps outside the Highline Ballroom to tell the guy at the door who, exactly, he may allow to bring a cellphone into the singer's sold-out gig. The list is very short.
"Like Queen Latifah," says Walton.
Benji Spanier nods and spreads the news to everybody else. This is a "phone-free event," he tells fans waiting in line. And that doesn't mean airplane mode. Spanier holds a gray, rubbery pouch in his hand. Your phone goes in here, he says, and then we lock it.
"What?" one fan grumbles.
Quickly, Spanier adds an important addendum.
You keep that locked pouch with you. Spanier also explains that if you need to use your phone, you can just come outside and he can quickly unlock it by tapping it on a metal disc slightly larger than a bagel.
The tension breaks.
"If you had told me you were going to put it in a locker, I'd have been pissed off," Kevin Schmidt, 37, tells him. "This is OK."
The pouch might not look like the latest techno-bling out of Silicon Valley, but it's become the go-to tool for a slew of artists - including Dave Chappelle, the Lumineers and Louis C.K. - trying to reclaim their live performances without going all Adele on their fans. Created by the San Francisco-based Yondr, it has been brought in for special moments: Chris Rock's warm-up shows before he hosted the Oscars; the "surprise" Guns N' Roses' reunion gig at the Troubadour in April.
The pouch has also been used for regular shows by those tired of seeing every note and punch-line churned into a series of blurry, streamable insta-clips.
"I tried all sorts of things," says Wesley Schultz, the Lumineers singer and guitarist. "If you yell at the audience or treat them like kids, they're going to act like kids. You want to give people the responsibility and put the onus on them, but how do you do that?"
The pouch, he says, is the best option he's seen yet.
"Because people still feel they still have their baby in their arm," Schultz says. "It's a little bit clunky but it's better than telling them to leave their phones in their cars or forbidding it."
Graham Dugoni, 29, Yondr's founder, is a former college soccer star who, after graduating from Duke University with a political science degree, tried his hand at finance but found himself increasingly drawn to music. He had an epiphany while watching a guy dancing at a festival.
"He was pretty drunk, and two strangers were videotaping the guy, and I watched them, over their shoulder, posting on YouTube," says Dugoni. "If a guy can't go to a concert and just kind of let loose, what does that do to all interactions in the social sphere?"
Dugoni started Yondr two years ago. He tested prototypes of the pouch at a cabaret show in Oakland and also at a school in Portland. Eventually, Dugoni cashed out his IRA, sold his Jeep and found his first real investor, raising about $100,000 in total.
Electronic artist ZHU signed on for a series of shows. Comedian Hannibal Buress, whose YouTube'd comments about Bill Cosby in 2014 made him famous - a fact that came to annoy him - hired Yondr for a gig in 2015.
During Oscar weekend, Rock and C.K. used the neoprene pouch for shows at the Comedy Store in Los Angeles. Dave Chappelle, an early booster, brought in Yondr for shows this month.
Dugoni says the pouch serves two purposes. The artist can try out new material without worrying about it being leaked. Fans will also realize that they actually enjoy a show more without constantly filming, texting and Tweeting.
"If you haven't been to a phone-free show, you just don't know what you're missing," he says. "There's something about living in real life that can't be replicated."
In the line outside the Keys show, not everybody was so grateful.
"In this day and age, my phone is how I keep my memory," said Gerard Little, 24. "Chris Brown. Jason Derulo. I have their footage on my phone. If you don't want your music heard, then don't perform it."
Andrea Ostolaza, 29, said she wanted to share the concert with her friends who couldn't get in.
"If it doesn't have a flash or light, I don't feel like it's disrupting," she said.
Others embraced the phone-free zone.
"Nobody values people's music, nobody values release dates, and when music gets leaked, it destroys the mystery," said Ahtivah Lawton, 22.
"It's annoying when people have their phones out, lights blaring," said Jackie Coward, 53. "They can't stop texting. It's disrespectful, and I like Alicia Keys. I don't need to put out her stuff early. They should do this in more places."
For DJ Walton, the manager, the only real issue is that Keys planned to premiere songs from her planned follow-up to 2012's Girl on Fire.
"We don't want the first time you ever hear a song to be some (lousy) mp3 somebody captured on their phone," said Walton.
"We have a 30-foot stage and you're looking at it through a four-inch iPhone. We want people to come and almost forget about their phones for a moment."