A new Firefox extension, Greasemonkey, has some interesting implications. GM lets you run user-defined scripts that modify the html of pages as they are downloaded for viewing.
One such script is Butler. Among other things, it lets you bypass the saving restrictions on Google Print books.
Now that I think about it, one thing was not covered at CiL: hackers (I lose the term losely here). Odds are almost certain that any security placed on digital files online will be cracked wide open. Take iTunes for example; their DRM encoding has been bypassed twice in the last two days.
Granted, your average consumer is not going to use these techniques, or even be aware of them. But the threat of cracking and hacking is real, and needs to be taken into account when using computers in libraries.