In the name of science

Yes, quite frankly. A human life is quite precious. That's the sole and strong reason for my argument.

And of course your results in your experiment would have been different. However, telling the users the purpose and telling the users the consequences are two entirely different things. They are not the same thing.

And so we test on human life to discover its mysteries. When people decided it's unethical, they tested on animals. Then they decided it's unethical to test on animals. What then, are you going to test on? Also keep in mind that animals are not as mentally developed as humans.

Yes, it is the same thing. Suppose the following:

You designed an experiment where you want to test which areas of the brain are associated with relief. You would fire humans using a catapult and effects on their brain by scanning them immediately after. To carry out this experiment, you ask 100 people to participate in the experiment, in which all agree.

Before the experiment happens, you isolate the subjects, where they are taken one by one to the catapult. There, you blindfold them and tell them that they can potentially die in the experiment, and that their brains will be scanned shortly after they fall. They will likely be unconscious, however, might be in extreme pain if they do not lose consciousness. They cannot sue because the legal contract states that they are not responsible for any risk or injuries associated with the experiment. Thus, they MUST proceed with the experiment.

You load them into the catapult and you fire them. However, you do not tell them that there is a safety net on the spot they're going to land.

I'm pretty sure that you would agree that the results would be much more different if you had told them they cannot die from the experiment.