Price-bots can collude against consumers

MARTHA'S VINEYARD, an island off the coast of Massachusetts, is a favourite summer retreat for well-to-do Americans. A few years ago, visitors noticed that petrol prices were considerably higher than in nearby Cape Cod. Even those with deep pockets hate to be ripped off. A price-fixing suit was brought against four of the island's petrol stations. The judges found no evidence of a conspiracy to raise prices, but they did note that the market was conducive to "tacit collusion" between retailers.