You're lucky; you were number 6 on my list of possible options of getting a speaking invite letter to Joss at con, but the first two both panned out and I confirmed that he got 'em. If I'd used you, his expression probably would've been even more severe. : -)
In all honesty, he was mugging. We talked briefly while he was there -- he was being mobbed, to be honest -- and he seemed genuinely interested in who I was and remembered me when I saw him later. Incredibly gracious and kind, with a fair amount of snark thrown in. *grin*