Unless something changed, nothing forces you or anybody to access the terms of the mechanical turk. Use it or don't.
Writing a review of the Turk is fine, but pulling in "employment lawyers" is completely pointless.
"Trade unions disagree, saying that anyone undertaking work deserves proper remuneration."
Of course, unions don't like competition; they will try to take advantage of government power to get some competitive advantages for its members. But if you listened to unions, we would also get ride of productivity tools and make free contributions to open source projects illegal.