[KeithMajhor]

I'd never heard of them before. I wonder if they keep the old scans and resell duplicate books. They could make a bunch of extra money on half.com or similar. Depending on how they're scanning the books it'd also save time. Then again, it could be that they're required to destroy the scanned book in order for it to be legal.

[breathesalt]

Having run a textbook scanning service (http://www.ptrfy.com/) for a while now, I can say assuredly that keeping master digital copies or the physical processed books is a substantial legal liability.

[sdmn]

Would it be possible to avoid the problem by storing scanned books in an encrypted form where the key is some words from random page?

[dbaupp]

The process to digitise it they use ends up partially destroying the book; at least, it removes the spine ("step 2" of http://1dollarscan.com/works.php). They do mention that they keep the book around for 2 weeks (to allow rescans) but then they recycle it.

However, doing some more research, it seems that for certain items they can return it:

  Q. Are books ever returned?

  A. First of all, please understand that we do NOT return 
  any books after they are scanned. The books are recycled 
  after they are cut and this is part of our operation  
  practice.

  The exceptions for returns are for photos, material you 
  wrote yourself, material you own the copyright to and 
  only a few more. If one of these exceptions or a similar 
  exception applies to your order and you want the items 
  returned, then please purchase a return option($5) at the 
  time of your order.

(http://1dollarscan.com/faq.php)