"In a story just dripping with irony, Amazon Kindle owners awoke this morning to discover that 1984 and Animal Farm had mysteriously disappeared from their e-book readers. These were books that they had bought and paid for, and thought they owned. Apparently the publisher changed its mind about offering an electronic edition, and apparently Amazon, whose business lives and dies by publisher happiness, caved. It electronically deleted all books by George Orwell from people's Kindles and credited their accounts for the price. Amazon customer service may or may not have responded to queries by stating, 'We've always been at war with Eastasia.'"
Amazon Pulls Purchased E-Book Copies of 1984 and Animal Farm
The move was an accident but it shows what may be a future problem. I don't like the fact that data that I put on my machine may be altered or deleted at whim. Data must be protected. Once the data is installed on your device it should be IMPOSSIBLE for the publisher (and ideally anyone else) to remove or alter it.