I was at the Chrome Dev Summit - we got 75% off coupons at registration, so it was advertised as for attendees only. Even so, it wasn't a real coupon code - you go to a site, enter the code, and tell them what app you're working and they get back to you. Not quite sure how "required" that is, but they were required form fields
Speaker here. The discount codes were intended for the attendees, are unique, and they can not be redeemed twice. That said, I'd keep an eye for any Black Friday/Cyber Monday deals.