For at least the last ten-fifteen years neither of us answers phone calls from unknown callers. Call display is a great tool. Two calls from UK numbers just this week that we did not bother picking up. No message of course.
For even longer, neither of us bothers with mail from unknown persons, firms, etc. It goes straight to the bin. We cannot be bothered opening unknown mail adressed to resident, addressed to us, or addressed to previous home owners. Since moving most of our personal mail to the web ten years ago it is surprising how little relevent mail we actually get. Nor do we open email from sources/adressees that we are not familiar with.
If we answered those phone calls or opened/read that unknown sender (to us) junk mail it might be a problem.
I really do not know nor do I want to find out by changing our practice.