An "unsuspecting person" refers to someone who is unaware or has no reason to suspect or expect that something is going to happen or that they are in danger. Full definition
It was a shocking sum, representing the hard work and hopes of dozens of unsuspecting people who had put their trust in a respected businessman. (realtormag.realtor.org)
But some dogs will hide their cherished things around the house and guard them from unsuspecting people or animals who have no idea that they're anywhere near a valued object. (pets.webmd.com)
Sadly, these scenarios are common and have happened to many unsuspecting people. (aspca.org)