how does the human setting work anyway?

hi, any one know? how does the human setting work anyway?
wouldnt it bother the user as well as the "bad humans", and any friends visiting too?
Can humans hear it, and wouldnt it drive them crazy?

Also wondering: my problem is theres been this rat living inside my wall, and i need to make him want to vacate! Hes buliding his nasty nest, peeing, scratching and gnawing, drivind me crazy hes so loud and smelly!
So, will this app make him want to leave, now that hes already settled in?
Thanks!

coatliq about Ultrasonic Repeller, v1.1