It's safe to assume that The Smiths have one fewer fan today, albeit – like a Patsy Kensit-less Strictly Come Dancing – one they won't particularly miss. David Cameron may adore This Charming Man – as a vital, yearning ode to disaffected youth or even a focus group-selected hit point with the affluent thirtysomething demographic. But either way the chances are he won't be able to listen to it again without a twinge of resentment, humiliation or that eternal burden of the lifelong Smiths fanatic, rejection.

If he was merely racking up young person's "cool" points with his repeated lauding of Manchester's most winsome on Desert Island Discs and the like, he picked the wrong band. Morrissey nailed his colours to the anti-Tory mast with Margaret on the Guillotine way back in 1988 (surely such a devoted Mozmaniac would have known that, David), and Johnny Marr this week made a more pointed parry. "Stop saying you like The Smiths," he tweeted at Cameron, "no you don't. I forbid you to like it."

Marr's ear-steaming outburst is in the grand tradition of musicians baulking at their credibility being used for political gain; see also Damon Albarn refusing to attend a Number 10 reception shortly after Tony Blair's first general election win, or The XX's fury at one of their songs being used at the Tory conference in October. Having named a Radiohead album Hail to the Thief as an attack on George W Bush, Thom Yorke was appalled to find that a Daughter Of Dubya's had even watched the band live in 2006.

But there are greater inferences at work here. If Marr can trim Cameron off the Smiths' Facebook followers list with a personal banning, he might just have discovered the holy grail of musician/fan interface – a way to fine-tune your fanbase.

For decades, unexpectedly successful alternative bands have found themselves hating large swathes of their own fans, and going to extreme lengths to ditch the chaff. When Radiohead found themselves barraged by hair-rock jocks on US tours, they stopped playing Creep live and went electro.

When Kurt Cobain saw millions of people who'd have bullied him in High School turning up to his gigs, buying his records and wearing his mascara, he made the challenging and visceral In Utero to scare them off.

True, Oasis pulled off no musical U-turns to shake off all the lager-lobbing Neanderthals who have made their gigs insufferable vomitoria since about 1997 but, at the other extreme, Metallica were so upset to have download-savvy followers as early as 2000 that they set about individually suing them, one by one.

So has the personalised cattle-prod of Twitter opened the door for bands to prune, hand-pick and refine their fan base like some kind of musical Mensa? By tweeting off the undesirables, can bands now choose their own fans? And could it go further? Will we ever see breathalysers on the door at Kasabian shows? The fashion police manning checkpoints at Lady Gaga gigs? Or even Myspace pages featuring a personality test, credit check or iTunes library screening procedure before allowing the applicant access to their music? Foolhardy as all this would be for the established acts, for a new band seeking a canny publicity angle it would be a brave, brilliant move – in a world of unlimited access, exclusivity is the ultimate prize.

For the time being, though, Marr has made a noble stand, proving that it is possible to scrape stinking wads of politician off of your cultural boot-heel. We can only hope, to prevent their work being similarly stained, The Killers, REM and the estate of Benny Hill follow suit.