That happens today all the time. We'll sell an e-book that goes with that printed text. You could somehow prevent just sending out 300 copies through some digital mechanism, but what mechanism is there to prevent photocopying half of this particular book? I am not aware of any mechanism to do that, other than the fact that current law says it is not appropriate, and people respect that.
On March 6th, 2012. See this statement in context.