I'm thinking about using MT for a more mentally intensive task: have each HIT involve reading a paragraph or two of a given text, and write pairs of questions and answers that could be obtained from the text. Is this feasible?
Be clear on what you want them to do.
pay them decently, not 1cent, maybe more like 5 cents or more
and test it out, see what kinds of data ya get back, tweak, and change it up
Most turks aren't going to be BS ya but some will, in the end however you only pay for what you feel is quality, but if you deny folks over and over and the reason you're getting crap data is not them its because your HIT is too vague and you pay crap, well you'll get a rep for being lame on turk and more crap data will follow.