One way the authors tested whether people read forms was to have students fill out a thee-page consent form to participate in a study. Here's an excerpt which I suspect will become a classic:
The second paragraph was a long-winded explanation of informed consent, but buried three quarters of the way through this paragraph, was a sentence suggesting that participants should not sign this consent form as its terms were clearly not in their best interests. The third and fourth paragraphs described unproblematic aspects of studies typically conducted at the university. Buried within the fifth paragraph, however, were clauses that were certain to be unacceptable if read by participants. In particular, these clauses committed participants to administering electric shocks to fellow participants, if instructed to do so, even if that participant screamed, cried, and asked for medical assistance. It also required participants to do push-ups, if the experimenter instructed them to do so. Contrary to human-subject protection guidelines, the form required participants to remain in the laboratory until and unless the experimenter allowed them to leave.
So how many signed? 87 of the 91 participants, or 95.6%.
So - you may want to actually read those contracts!