Have you filmed someone and shared it without their permission?

I imagine it varies from one country to another, but in the US if you make no profit from the film and/or you're in a public space(street, pub, library, etc) it's fully legal and you cannot be prosecuted for it.

That being said, if a person makes it clear they do not want their faces shown on the video and the the guy filming does, it's common courtesy to blur their face or don't use that footage.

But I could be wrong.