So a single programmer is going to spend 100% of his time trying to make a "unique lock" and a "unique password" for each d/l? It's a losing battle, there is literally no way to stop a determined reverse engineer (short of dedicated hardware that actually performs complex computations, rather than challenges and responses, and even then someone could emulate that in software). It's also a horrible business decision, for multiple reasons (pissing off paying customers, spending too much time on something that isn't important, etc).

Mod parent up please - this is spot on. Fair use is not what you think of as "fair", and everyone's guesses have been horribly wrong. Even people that find the wikipedia article that lists the important factors then proceed to analyze the factors wrong, as they don't know the law.

It just happens that on Sunday I was talking to a a lawyer who used to work at one of the premier IP firms in the US. I asked her what it would cost to defend against a claim of copyright infringement if you thought you fell under fair use. Assuming the other side doesn't mind paying for their lawyers to play the game, and you'll get all sorts of discovery requests and all that, you're looking at $200k to defend. Yes, that's $200,000. Of course that's one of the biggest IP firms in the nation, but you get the idea...

This needs to be modded down as it is comically inaccurate. Additionally, if people read this and think "hey I used less than 10% I'm cool" they're going to be in for a big surprise when the lawsuit arrives.

There is no such thing as a 10% maximum on fair use, and you won't find anything about 10% being a magic number anywhere in copyright law. Even the most basic research into fair use will show you this.

Additionally, critical commentary can have a harmful effect on the market for the copyrighted work and still fall under fair use (look at the Scientology cases).