Ah, yes, worded in such a way that you can feel good about helping humanity. I guess there ARE some legitimate studies out there, but unfortunately with the intrusiveness of our national governments, and the losses in our rights to privacy, it's easier to doubt than to trust. (And believe me, I would doubt first, trust later.)
I'm guessing you don't even have to respond. I mean, what can they do? What about anyone who was out of the country when the letter came? What if the letter were lost in the post? What if your dog ate it?
alys