As fans filed into Webster Hall in New York City last week, a note from indie rock band the Yeah Yeah Yeahs wasted no syllables in laying down the law.
"Please do not watch the show through a screen on your smart device/camera," it said, along with some stronger words unrepeatable here.
During the gig, vocalist Karen O repeated the request, telling fans to take a picture right at that moment - but to then keep devices hidden for the good of those around them.
On the web, news of the band's defiance against the march of the amateur filmmaker spread - and was met with whoops of delight from many music fans fed up with seeing mobiles thrust into their line of sight at every public event.
Many of them longed for the days when the only thing illuminating the crowd at a packed gig would be a sea of cigarette lighters, held aloft during the more tender moments - and not, as is now more often the case, the glow of the mobile phone.
"I would never turn on a cell phone at any musical event," wrote Roger Waters, former bassist and vocalist for Pink Floyd.
"It would seem to me to show a lack of respect to and care for fellow concert goers, or for that matter the artist."
"Apart from anything else, how could I possibly truly experience the thing I'd paid to see and hear, if I was fiddling with an iPhone, filming or twittering or chatting or whatever?"
'Weak and distorted'
To make matters worse, the type of footage recorded at gigs tends to have, as one Guardian journalist put it this week, "audio quality that would make Simon and Garfunkel sound like Slayer".
Sophisticated as it may be, your smartphone's microphone is only capable of capturing anything and everything immediately around it.
But one company emerging from Dublin's blossoming start-up scene thinks it has the answer - and appears to have record labels on its side.
"What our unique proprietary technology is able to do is take the poor quality on-camera audio from fan videos, and we analyse that and can see the patterns, even though it's very weak and distorted," explains Cathal Furey, co-founder of the firm, 45sound.
"The technology takes those patterns and matches it against what we call a master audio recording, which would be a professional live audio recording [from the same gig]."
From here, clips are re-uploaded with the high-quality audio, and in cases where there's more than one recording of the same moment, fans watching the gig on 45sound can switch camera angles.
In recent years, several sites have sought to make use of the swathes of fan footage recorded on a nightly basis.
Apps such as Vyclone have been used by the likes of Ed Sheeran to "crowdsource" gig footage, with fans being encouraged to upload their recordings of Ed for it then to be edited together for the official music video.
Another start-up, OutListen, gathers fan videos and, if there's sufficient interest, will go to record labels after a big show and request the professionally recorded audio.
But Mr Furey believes it is 45sound's audio-matching software which gives it the edge over rivals - meaning no human intervention is needed in order to whip the clips into a listenable state.
"It's all completely automated," he says.
"What we're trying to build is a scaleable company. I'll be happy when one day we do a thousand shows in one night."
Vital to this scalability is in building relationships with record labels. To that end, 45sound has the ear of several companies - including Sony Music-owned RCA Records.
One of their acts, Bring Me The Horizon, has been trialling 45sound on their latest tour - prompting fans to record their show and upload it after the gig.
"It compliments the whole marketing plan," says Justin Cross, head of digital marketing for RCA.
"A lot of the artists we work with at RCA are live bands - if you're watching someone's video of Bring Me The Horizon and you can see for yourself how fantastic they are live, you're probably going to want to go and see them."
As part of their trial with 45sound, Bring Me The Horizon's vocalist Oli Sykes prompts fans during the gig to record one particular song.
For those who hate people recording, it may seem an irritating, even inconsiderate request - but it is somewhat tactical, the 26-year-old tells the BBC ahead of the band's gig in Bristol.
"When we did it in Leeds the other day it was almost like it got it out of everyone's system.
"Everyone filmed the song, and then everyone put [their cameras] down and everyone got back into it
so it was cool."
'Put your phone down'
Meanwhile, in the shivering cold outside the venue, Bring Me The Horizon's fans are divided in their views of gig etiquette.
"People behind you are like 'put your phone down we can't see'," says one female fan.
"I think people kind of like just want to just get into it without standing around with your arm in the air all the time filming."
Another fan, male, has more enthusiasm towards the web's possibilities.
"It's always good when people film it, you can go on YouTube and see it, and relive it, and see all the people in the comments talking about it - you can make more friends with that as well."
For record companies like RCA Records, it's a situation that requires delicate compromise, says Mr Cross.
"From a label perspective, and my perspective as a fan, it's something that's just part of a gig now, you can't get away from it.
"On one side of things, it can be quite annoying for the fan that isn't into doing this, but on the other side it's helping to push the band."
But 45sound's Mr Furey argues some events are just too good not to be widely shared.
"I can definitely see that having a sea of cameras can ruin the experience. Ultimately the most important person is the person who pays for a ticket to go and see the show.
"At the same time, I've been at other events where my first reaction is 'who's videoing this?'. Live music shows are an incredible human event - they're very tribal, very powerful, very emotional."
So while the Yeah Yeah Yeahs join a select group of grumblers that includes the likes of Jarvis Cocker, Jack White and the Stone Roses - it is likely that the "sea of cameras" is here to stay, and not just at gigs.
"I have that problem in general life myself," reflects Bring Me The Horizon's Mr Sykes.
"I find a lot of people are documenting too much stuff... rather than just living it."