It looks like Radiohead have been reading Freakonomics. They plan to use an honour system to sell their next album, asking fans to pay as much or as little as they want - just as bagel-seller (pdf) Paul Feldman does in Freakonomics.
The thing is, not only are such systems quite common, they also work. Feldman has a payment rate of almost 90%. More promisingly for Radiohead, Canadian singer Issa has a choose how much to pay system, and finds that 94% pay at or above the suggested price for a downloaded track.
Such systems demonstrate that social norms really work. People behave honestly even when they needn't - they obey the social norm of reciprocity.
So will Radiohead's system work? What they have going for them is enormous brand loyalty, and the hope that fans will pay over the odds in anticipation of reaping enormous consumer surplus. Against this are three things:
1. Fans won't know the quality of the tracks in advance - will it be another OK Computer or Hail to the Thief? - and so might pay under the odds to reflect this risk.
2. As far as I know Radiohead aren't suggesting a price, giving fans no reference point of how much to pay.
3. As Radiohead are much richer than their customers - unlike Issa or Paul Feldman - people might decide that they can afford to give their work away.