Gangs are watching gigs to see who's filming the stage on a nice smartphone, then nicking it from their pocket in the ensuing crowds, according to a Metropolitan Police warning.
The Met will be putting up posters at venues and providing Bluetooth messages telling punters to put their phones away, and perhaps enjoy the gig rather than recording it, badly, for later review.
Nev Nolan of the National Mobile Phone Crime Unit said: "A lot of people like to use their mobile phones to film or take photographs of the concert, but will then return the phone to an insecure bag or pocket, where thieves are able to snatch it."
He stopped short of reminding them that recording a gig is piracy, but instead pointed out that many victims never realise know they had their phone stolen - assuming it lost - and thus don't report it, which means the handset will continue to be usable.
Snatching mobiles has fallen out of favour with thieves, thanks to an international database of unique serial numbers (the IMEI) which prevents stolen handsets being used. That shifts the crime to a more technically-literate gang who can change the IMEI or shift the handsets to one of the few remaining countries which haven't mandated use of the database.
We've certainly considered tapping someone on the shoulder and asking why they were apparently filming an entire gig on their mobile phone - but then we're old-fashioned enough to think something's worth doing even if there's no Facebook evidence to show we did it... ®