Illegal, no. Wrong, Yes. Good idea for Company, Yes and No. You bought a key to play the game and a cd containing the files to install the game, not the game itself. By installing the game you agreed to the license agreement they showed you. If you notice, 99.9% of license agreements have a clause stating they can change any part of that agreement at any time. It is not smart as CS 1.6 is free, and it honestly isn't costing Valve much if any to maintain anymore, but they want to make money. So they'll find a way to do it. Sad some of the best games are ran/supported by them, cause they honestly have the worst history of customer care/support.