The idea that you would feign solidarity in a social experiment with real consequences so you could screw fellow students surreptitiously is just as bad (I would argue worse) than the intimidation you are presuming existed. In fact, even under the presumption that intimidation occurs, you are admitting to happily screwing over other students who would have been happy to take the test, but for the intimidation. So the fellow victims of the "crime" get punished once by them, and then again, by you.
If you actually want to take a principled stand, you'd have to do something shocking like.. be honest with everyone with what you intend on doing, and why.