DMZ2112
Chaotic Looseleaf
For my part, I've always found "you must bring the hardcopy book to the table" to encourage more of a CCG mentality than allowing printouts off the Internet - it creates the same atmosphere of "pay extra real-world money for in-game effectiveness".
Even ignoring the fact that PDF downloads of roleplaying books generally still cost real-world money, this is not an apt comparison. RPG and CCG purchases serve very different purposes. A dungeon master requires his players to bring all the rules applicable to their characters to the session because he lacks an encyclopedic knowledge of the system, not because those books somehow enable or improve the player-characters. You can theoretically play any character available in D&D without a single purchase, but if you tried to pull that off at a Magic game (even a friendly one), you'd get laughed out of the room.