The phrase "unsuspecting populace" refers to a group of people who are unaware or have no knowledge about something that is happening or planned. Full definition
I find it both mildly disturbing and amusing that you think that the entire beef eating population, some of whom have died after eating pink slime by the way, should somehow feel bad for a handful of people who had no problem at all whatsoever pushing such a disgusting product onto an unsuspecting populace. (thelunchtray.com)
While it's an outsized persona, the first season's Lorne Malvo (Billy Bob Thornton) is a malicious man who delights in the torment and pain he visits upon an unsuspecting populace. (blog.bullz-eye.com)
What's more exciting than creating your very own infectious disease and unleashing it upon an unsuspecting populace? (droidgamers.com)