After reading the agreement fully, My interpretation is Yes. An AWD is a corporate Account number.

C. 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.

For additional drivers/employees. The following must occur:

you need to rent via your AWD from your business. Both you and your additional driver must be employed with the company attached to the AWD at the time of rental and the rental's primary purpose must be a trip that is designated a business write off* or 100% paid by the company through reimbursement or direct billing to a charge acct owned by the company.

*Business Write off is an interpretation, not written doctrine by avis. I know many locations use this interpretation as there are businessmen out there who have their own AWD numbers for their own self business but pay out of pocket for expenses. Not all locations would agree, but I believe in a court of law this argument would hold based on current language.

The only change is that the business awd must be used. In practice, everything else is identical to current real world implementation.

Scenarios.

Rent car from priceline-You and spouse are only authorized drivers
Rent car with company AWD-Any employee on the same trip for the same purpose can drive
rent car with discount AWD from Flyertalk's forums-you and spouse are only authorized drivers
Rent car from travel agent-Varies. Need to make sure your TA uses your AWD, but it may change your rates.

Bottom line, if your the only driver, this statement means nothing to you. But if you are planning on others driving, make sure the company AWD is used.

The email mentions that my next rental will constitute acceptance of the new regs. Does this mean that my next (Preferred) rental will necessitate signing anything, or can I go straight to the car as usual?

Thanks.

as usual, go straight to the car.