folks, there's a big difference between dodgy links coming up in searches, or even accidentally clicking a link to something. These things, at worst, get you to the front entry page of an questionable site. Most of us have had this sort of thing and, thankfully, it's becoming less prevalent.
I think the point here is can you accidentally end up viewing extreme/illegal material? The answer has to be no, there is no way to that material without a serious search or the entry of payment information. Claiming it's for research purposes for a book doesn't wash either!