The developers of the fine game Galatic Civilizations really got it what a copy protection system is supposed to do. This is what lead designer Brad Wardell has to say (quoted from here):

What other publishers do to protect their intellectual property is up to them. I simply don’t [think] CD-based protection is particularly effective. Any copy protection system, in my opinion, should be focused on trying to increase sales - not stop piracy. The two aren’t the same. Most people who pirate a software product would never have purchased it. It’s pointless to waste time on those people. The people to focus on are the ones who might have bought your product or service but chose not to because it was easier to pirate it. The question is, how many legitimate gamers choose not to buy a game that has CD protection because they’re on the fence and know that sooner or later, they’ll probably lose that CD?

Finally someone with common sense!