Instinctively, you know where your sympathies ought to lie. She's a twentysomething pop star of moderate ability, who's become filthy rich by co-opting the attitude of punk rock and sanding off all the uncommercial edges. They're a band from the 1970s, alumni of the cultish Beserkley label, back on the road for the delectation of a small but discerning fanbase.
But when Tommy Dunbar, guitarist for the Rubinoos, alleged last week that Avril Lavigne ripped off his 1979 song I Wanna Be Your Boyfriend for her worldwide hit Girlfriend, I felt some sympathy for the Canadian chanteuse.
Allegations of plagiarism are rife in rock music, and no one is immune. John Lennon was sued by Chuck Berry because of similarities between Come Together and You Can't Catch Me; George Harrison had similar problems when My Sweet Lord was deemed to be too close for comfort to the Chiffons' He's So Fine. The Beatles had their revenge in the late 1970s when they took all the publishing royalties from the Fabs pastiches that Neil Innes created for the Rutles; and the merry-go-round continued in the mid-1990s, with Innes acquiring half the cash from Oasis's Whatever, after a judge deemed it to be not a million miles from his How Sweet To Be An Idiot. Oasis were serial offenders in this respect, merrily lifting from T Rex, Stevie Wonder, the New Seekers and - stop me if you've heard this one before - My Sweet Lord.
If the allegations are true then, Lavigne seems to be following an estimable tradition. But does Dunbar's complaint really stand up? The tunes do sound similar, and the lyrics of the chorus are verging on the identical. However, rock music at its primeval best has a very limited number of chords at its disposal. Its lyrics are similarly constrained: love, adolescent rebellion, or any combination of the two. Is it any wonder that, after more than half a century of three-chord tricks and variants on "I love you, Peggy Sue", everything starts to sound a bit samey?
Rather than making plagiarism the subject of lawsuits, musicians should turn it into a game for rock nerds. Joyce and Eliot packed their works with references to past writers, and readers and critics are still winkling them out. Songsmiths could set up premium rate phone lines for fans to identify riffs borrowed from Chaka Khan or couplets purloined from Roger Whittaker. Proceeds could be donated to the original writers.
Of course, some musicians have been playing this game for years. When the Smiths released The Queen is Dead in 1986, critics seized on Johnny Marr's riff at the beginning of the chorus of There Is a Light That Never Goes Out, pointing out its similarity to There She Goes Again by the Velvet Underground, from 1967. Marr admitted that it was indeed half-inched, but not from the Velvets. It was based on the Rolling Stones' version of Hitch-Hike, to which Lou Reed had presumably taken a liking 19 years before. And I'm sure you can name any number of songs with a similarly convoluted pedigree.
And as for I Wanna Be Your Boyfriend, by the hard-done-by Rubinoos, the disputed chorus sounds remarkably like the Stones' Get Off My Cloud. This dispute could run and run, and Dunbar and Lavigne would do well to remember the first rule of such disputes: the artists rarely win.