Originally Posted by erk
A "completely hypothetical" method, would be to take an unmodified Nook device, download a number of read in store titles, and then power the device off before leaving the wireless network. If the device is then booted with a "piracy facilitation device" (aka, the widely available SD card images for Nook rooting), it is trivial to copy off the Read-in-Store files.
Read in store books aren't epubs that download. I've not tried to figure out exactly what they are, but they come down a page at a time when you are in the store.