Is it legal to have hidden 'Nanny Cams'?

[Aubrey0]

I'm working as a night nanny, meaning that I am at somebody's house from 4pm til 9am, I know that they have cameras because they are not secretive about it, there are big dome security camera in both children's rooms, the family room and outside the house. My question is, would they have hidden cameras in the room that I am staying in? I never thought about this and have been getting changed, going to the bathroom etc. I have a feeling they don't because I have been in three different guest rooms in the house when their family has been there and they stayed in the other rooms. If they do have cameras is this legal?


http://www.amazon.com/Baby-Security-Talkback-Activated-Compatible/dp/B019HDNLXS