Upload & Sell: Off
Monito, honestly the only way that could have worked is if they had gotten people to sign an agreement during the purchasing of a book. Because it is naturally quite easy for an item to be passed from one person to another, nothing could really stop that.
With a digital copy the the access control or use is provided by a facilitator so it is always up to them whether to allow the 'asset' to be transfered from one person to another. It is not their prerogative or duty to allow this, and if a third party tries to do this, they can get into trouble any number of ways legally (because they are just copying the 'asset', not actually transferring it).
This is one of the things that keeps the value of digital assets down, people expect it to be 'cheap' and don't want to pay full price purely for the convenience. This is why, for instance, iTunes doesn't sell full albums, only $1. songs, and so on. Really one could make the argument that it is the best interest of the facilitator to allow these transfers if they want to charge full price for digital assets, but it really depends on their business model, etc.