I think the (horribly misguided) idea is that even if you somehow figure out how to start an illegitimate copy of the game without authenticating, your game will still be crippled to the point of being unplayable. Unfortunately the same is true if you start a legitimate copy of the game with a spotty internet connection.

It should be noted that the book you linked is available for free online at http://www.rubycentral.com/book/ It's very good for learning the language.