Why did you have to look up a porn video just to see if it existed? Context and motive are important. For example, let’s say your friend tells you that her ex-boyfriend uploaded a sex video of her to a porn website. If you look for that video for the purpose of reporting it to law enforcement and having it taken down from the site, that’s a good thing to do. Or say you were searching for something innocent, came across an illegal video, and reported it to law enforcement, I think you could legitimately search to see if it’s still there, say, a week or a month later.