Tovi is very right here. The professional crackers you can't stop. But most of the others maybe.
It would be pirated by exactly the same number of people as a game with copy protection.
Not true. Unfortunately there are rarely numbers for it so every example you can find here is pure luck. But there are some.
My favorite one is a few years away. Any one remembers Incubation from Blue Byte? A hell of a game! Got everywhere very good reviews but sold terribly. Nonetheless the developers decides to get some of the costs back and throw an Add-On after it. It was just amazing. It went away like a flood. They even covered all their costs from the main game.
So they wondered why so many people bought an Add-On for a game they impossibly could have? The Answer was simple, the Add-On had a copy-protection while the original game didn't.
