See thats one of the big problems with the stigma around cask ale. People continue to use "warm and flat" in a joking manner, but realistically it just keeps the myth going. I don't see how it helps the situation, but neither does the "old man" image of cask in general.
Slightly OT but in reference to the old man thing, I had an english guy, late 20s, recently ask me though whether there was much point in CAMRA because 'everyone I know drinks real ale'.
He wasn't from London which is where a lot of the struggle seemed to be when I was there and there where still a lot of beards and wooly jumpers at the festivals...
My wife and I got truckloads of free stuff at these festivals because we where under 30, foreign and one of us was female. A dream demographic couple for them...
I have posters, framed prints, coasters, t-shirts etc. etc...
As to the flat and warm, well, I'd say it's hard to say if that keeps the myth going but possibly it doesn't help...
Boy do I miss my cask ales though