I can hear one scratching around late night. Sounds like it's tearing way at plaster, nut more than likely it's just running around under the floorboards knocking dust and debris around. I think it's true that human scent puts them off, I left a sticky trap under the stairs and it didn't catch anything for ages, but last week it caught two! And another one in the spare room caught one, bear in mind these traps have been left for over a month.