Just because a particular flight does not have R availability does not mean no flight ever does. I've seen plenty of R space. For example, ORD-CDG on 4/7 is R3 and on 4/8 is R7. You can turn around and come home on Monday and confirm that too.
I just flew in Feb 2015 to and from GRU with two GPUs confirmed in advance.
Also, how do you know they don't already have several people who confirmed with GPUs on that very flight?