Just because you can check the Camel book out at the local public library doesn't mean that it's legal to photocopy it cover-to-cover and begin selling copies for $5.50 in computer expos.

Violation of copyright laws are violations whether they're easy to accomplish or hard. Website policies may, in many cases, be easily violated. But the ease in which it is done doesn't mean that the policy is without legal basis, nor that your violation is really just the harmless act of a legitimate opportunist.

If I leave my car door unlocked you might open it while I'm not looking and help yourself to a few of my CD's. Is that any less of a theft than if you had to pop the lock open with a slim-jim to get those CD's?

Play it safe by sticking to the site guidelines, and when in doubt, negotiate a deal with the business up front rather than in the court-room after the fact.