With all the other ways your cards can get charged with out you knowing or your consent, I think it is just part of the game. All you can really do at this point is exercise personal responsibility and check your card statements a couple times a week for fraudulent charges. The banks and the like aren't concerned about looking out for you at this level. Living in Salt Lake City though, I'm probably going to give this a try, even if it's only for novelty value.

Herd immunity sounds a lot like: Welfare, This means that even though you don't have a job for whatever reason, you're still safe as long as everyone else does.

That is true, but Microsoft products are relatively ubiquitous, so it was probably very easy for them to use MS as an excuse to raid these groups. So they would have to either find out the group is using a particular software illegally or manufacture evidence of such to get the same effect.