This is not to say that they aren't reasonably competent musicians; the scene where Nat is jamming out with Cindy Lauper has to be seen to be truly appreciated. Though most of the "live" music scenes are actually lip-synced, the notes and rhythms being played are true to the sounds that the viewer hears.
No, the reason for the disclaimer is the reason this is a reasonably decent movie. If you are paying attention and you are a casual Beatles fan, you will notice the allusions run thick throughout. If you are a hard-core Beatles fan, you'll notice that the fictional "Silver Boulders" were modeled on the very real Beatles.
The plot line of the former should be familiar to anyone who knows the history of the later. Of course, in this version no one ends up getting shot and the band comes back together. But the pivotal events of both bands (up to and including the band's break-up precipitated by an Asian love-interest) happen to line up surprisingly well... Almost as if it were a mockumentary and not the serious documentary it actually is. The finale, a reprise on the roof of "Crazy, Crazy Car" (the Silver Boulders' chart-topper), is a classic call-out.
Unlike many other shows on the Nickelodeon network, NBB is a surprisingly smart take on tween entertainment. It has its detractors already, but this reviewer's gut feeling is that they weren't paying attention enough to notice the small flickers of genius underneath the rather more commercial silliness that makes this movie (and the soon-to-come half-hour spin-off) a viable market proposition.
If this show maintains its integrity (more likely than not, since it maintains its writing and producing teams intact: namely, Polly Draper, mother of the show's stars Nat and Alex Wolff), it could turn out to be a surprise. Placed against its competition, mostly cute middle-school sit comes or the insipid star vehicles infesting the Disney Channel, NBB comes out on top. It's honest, amusing, at times a bit saccharine, but mostly surprising.