The problem lies within the end user accepting every term of that new software they downloaded. This also happens to include all sorts of fun programs. Just had to go to my moms to clean out "The Weather Channel App" and several other search security add ons and bullshit from her 8.1 PC I built. They don't visit risky sites, my brother just doesn't pay attention to what he is clicking when he downloads bullshit programs his high school requires him to use for homework assignments. He uses Oovoo for whatever the hell reason and that will install several ask search programs and bars as well as another random program that is a pain to deal with.
Shhhhhhh...all that crapware keeps us IT guys in a job.