If mturk is the back end, you need to tell users that a human will listen to their voicemail and look at their stuff. I assumed you had voice recognition software and clever image stuff, not random humans. The privacy issues of this are horrid; at least make it obvious what will happen.
Yes, you are right. How about a strap line across the bottom:
"Powered by Mechanical Turk: humans write these answers"
I'd put it at the top:
Email an attachment to
go@mail2brain.com
and a human will turn it into something useful:
Frame it as a feature :)
Email an attachment to go@mail2brain.com and a real person will turn it into something useful
Very much so! It would also stop people from emailing something then assuming it's broken when they don't get a reply a few seconds later.