Surely a minority, but it's steadily increasing even among non-technical folks. I see it all the time nowadays.

Not as small of a minority as you think.

They hand them out for free at my wife's work I think.

Sometimes that minority may be surprising. I have seen people who are otherwise very careless about their computer's security put tape over their computer's camera.

When you think about it, it makes sense. People frequently bring their computer into private spaces. Where any given person draws that line will vary, depending upon their expectations of privacy. (One of the criticism I've heard of the recent shift to online schooling is the use of video conferencing, because some kids don't want to effectively invite all of their classmates into their home. This is hardly what I would consider a paranoid demographic and is a situation where you have a considerable amount of control over what people see and when.) Is it really that strange to suppose that some people will want to cover up their camera?