Just received yesterday the updated Terms and Conditions as a Avis Preferred Member:

3. Who May Drive the Car

Except where otherwise specifically authorized by applicable law, only you, your spouse or domestic partner, or, if you rent from us under your employer’s corporate account agreement, your employer or a regular fellow employee incidental to business duties may drive the car, but only with your prior permission. The other driver must be at least 25 years old and must be a capable and validly licensed driver.