Honor System Vs. Trust-But-Verify
I'm working on a feature on software licensing currently and in a recent interview, IDC analyst Amy Mizoras Konary told me Oracle is one of the few vendors that relies on the honor system, whereby it ships all sorts of software and lets you use it whether you have licensed it or not. It has no mechanisms, other than software audits, to alert you whether you are actually entited to use these features. The danger, or course, is that DBAs and app administrators will install, turn on, and start using all sorts of features only discover in an audit that they owe a lot more than they realized. Negotiated discounts could go out the window, too.
Most vendors take what she called a "trust but verify" approach whereby notifications are triggered when you try to use or install features that you're not currently entitled to use -- or at least the notification will warn you that it's an extra-cost feature that you have to be licensed to use. This helps avoid those audit surprises.