Sure, but you're thinking about that kind of stuff even slightly, you're not going to be uploading your documents anywhere. I suspect the Venn diagram overlap between "thinks about online security" and "uploads documents to random web sites, even if they cost money" is small.

If it's anything I need to care about privacy with, I'm not uploading it to someone else's server even if I pay for it, I'm doing it locally.

But if it's say, as a friend recently experienced, a handout from a teacher in Corel Draw format, you bet your ass I'm uploading it to whatever the top google result for "convert corel draw to pdf online" is.

I don't pay anything to use HackerNews. How much do you pay?