Should I feel guilty?

sign of the times
Originally uploaded by Box and Arrow.

I do this all the time, making note of ISBNs for later online lookup. Should I feel guilty for that? Should I not because I'm usually doing it in a Barnes & Noble or Borders? Should I if I'm doing it while in a small independent bookstore? On another note, saying "ISBN number" is like saying "ATM machine", it's redundant! (It's like saying "international standard book number number".)