Just found the terms of the promotion. It doesn't mention anything about not selling... or it being an upgrade. I'll give it a go and see what happens.
Terms and Conditions
Offer expires August 31st, 2012. VOID WHERE PROHIBITED, TAXED OR RESTRICTED BY LAW. For a limited time, eligible customers may purchase an annual membership to Adobe® Creative Cloud™ for a reduced price. Offer valid for purchases of an annual plan, which requires a 12-month contract. This offer is only available to customers who own a Creative Suite edition or individual product, version CS3 or later (CS3.x, CS4, CS5.x, or CS6), and who purchase directly from the Adobe Store or by calling a regional Adobe Call Center. This offer is not available to Education, OEM, or volume licensing customers. Residents of embargoed countries are not eligible. This offer is valid from 9:01 p.m. (PT) on April 23, 2012, until 11:59 p.m. (PT) on August 31, 2012. This offer is limited to one (1) purchase of one (1) Creative Cloud annual membership per customer. Offer is subject to U.S. export control laws and laws where the recipient resides. Offer may not be assigned, exchanged, sold, transferred, or combined with any other discount or offer, or redeemed for cash or other goods and services. This offer and prices are subject to change without notice. Void where prohibited, taxed or restricted by law.
Billing Terms for Annual Membership
Annual plan - $29.99 per month
with a one year contract
You’re signing up for a one year plan. Each month, for the duration of your plan, we’ll bill your credit card $29.99 plus sales tax. As soon as you’ve successfully completed this sign up process and your payment is confirmed, your membership will begin.
This promotional price is valid for a full 12 months. After that, we’ll renew your contract automatically, at the standard annual plan price, unless you cancel. The price is subject to change, but we will always notify you beforehand.
We’d hate to see you go, but if you cancel within the first 30 days, we’ll give you a full refund. Otherwise, you’ll be billed 50% of your remaining contract obligation. If you ever need to cancel, just call Customer Support.