Adding to this: the obvious problem with relying on a security system that is difficult for the "casual" exploiter but not for the dedicated exploiter is that it only takes one dedicated exploiter to develop and distributes a tool that casuals can easily use, it's game over. Each casual doesn't have to crack their game's copy prevention, remove watermarks, or discover their DVD's encryption key. They just have to all sit back and wait for the first pro to do it and release a tool. I've worked in software companies where I've questioned the efforts we expended on copy prevention, and it's always "yea this is to deter the casual copier", but it's futile because tools.