A home security system with a surveillance camera can actually be used to help monitor the safety of your children when they are in the house with the nanny or any other caregiver than yourself. Hopefully, you have enough trust in your caregiver's choices that this would not be an issue, but if there ever is a questionable incident brought to your attention, the truth will be spelled out in plain truth on the video tapes. Perhaps even knowing there is a house video monitoring system will be good incentive for the nanny to always be on her best behavior.

*Taken from http://ezinearticles.com/?Home-Surveillance-Systems-Give-Peace-of-Mind-to-Homeowners&id=2602473