How Publishers are defeating second hand books and piracy

At IIMA, we use several textbooks(all original and generally Indian reprints). While contrasting them with our Indian books, I used principles of marketing and microeconomics to understand certain things and thats what is being presented in this blog post. Besides the conventional price discrimination, there are other tactics all perfectly legal..to prevent mere ebook downloaders from profiting.

1. Enclosed CD's:- I agree that in quantitative subjects like Decision making, statistics and the like, shifting material to the CD does make sense and is cheaper than expecting students to access the net/ type into Excel. But for subjects like Marketing, OB..the use is dubious. 
2. Password linked student websites: Nearly every publisher uses this tactic to ensure that only those students with access codes can use the companion websites to learn. While some access codes can be legally purchased, they are quite expensive and.
3. Case Studies: As any management/law student knows, the case studies are best analyzed in class with the teaching note prepared for the Prof by the case author. By shifting text to case studies, the value is shifted from text to cases('which are hard to copy without teaching notes')
4. Audio Book/E Learning linked books: The Apple Ipad is eagerly awaited by publishers as a safe way to monetize their digital content.