But what's to stop me playing the game, and completing it, and then borrowing it to a friend? Again, this is no excuse...

Well nothing at all, and naturally I reckon we all do that. But it could never have the impact of install, give to someone, install, give to someone else etc.

I understand your frustration though...it's a pain switching cds about, especially for games that require you to do it while playing, like Baldurs Gate!

At the end of the day it's all based around the developers trying to keep their intellectual property from unauthorized users.

They have the right to try. If I was a games delevoper trying to make money I'd try to protect my products as much as I can.

The consequences of asking for the CD to play the game is an annoyance I imagine to players, but to the developers seeing your game available for download on the net because you didn't inculde any protection must be far worse. Ok this still happens of course, but wouldn't it be much worse if the CD didn't need to authorized at all.