The past contains lot of objectionable experiments. There was the famous Milgram Experiment, in which participants were made to believe that they were murdering someone. There was the Stanford Prison Experiment, during which students acting as guards or prisoners turned sadistic or masochistic just to see how far the experimenters would let them go. On the other hand, there's one series of experiments that I don't think goes far enough.
The tests are known as the Asch Conformity Experiments, and they're pretty moral. A group of people are put in a room and asked to give answers to questions regarding a card printed with a series of lines. In reality, only one member of the group is an actual subject of the experiment, the rest are members of the investigating team. The "ringers" give wrong answers to each question. The test is not complicated. It includes questions like, "which is the longest line" and "which line most closely resembles the length of the reference line." Anyone with eyes and a bit of care could answer all the questions correctly.
About seventy-five percent of participants answered at least one question wrong. When asked about it later, they said that they assumed that the group must have some knowledge that they lacked. In other words the rest of the group was so wrong, in such an obvious way, that the subjects believed they had to be right. Some people think the experiment was flawed. One major failing was the fact that the subjects were all young men, who might tend more towards insecurity than experienced older people.
I think it was wrong in a more profound way. The experiments showed that the more forceful and unanimous the group was, the more the subjects second-guessed their own eyes. We know that people can be pressured into being wrong. But can they be pressured into being right again? If someone has something important at stake, will they stick to the right answer? I suggest having someone come in and say something like, "If you get this wrong, I will key your car/kick your dog/kidnap your brother and hang him upside down and slit his jugular like in Taken 2." We know that people will fold under pressure, but that pressure goes just one way. If we put on contrary pressure, what will happen? Will people be even more likely to get questions wrong, assuming that there's safety in numbers if they answer with the majority opinion? Or will they insist more strongly that they are correct and the group is wrong? It's time to get a little evil.