Having some sort of video or audio recording device to check up on your child is pretty normal. In 2017, 75% of parents in the U.S. said they use a baby monitor. 39% of those parents said they use a monitor with a camera. It seems appropriate when the child is a toddler, but when the child is older, that becomes a serious privacy violation.
This woman, for example, was 25 when she found out her parents were keeping tabs on her with a hidden nanny cam. When her boyfriend found it at their condo, she confronted them. Their excuse was wanting to make sure she wasn’t being intimate with her boyfriend. Appalled and hurt beyond reason, the woman asked for advice online on what to do next.