How do you feel about nanny cams? Do you think a parent should have to tell the sitter about it?

I just purchased one. And I don't plan on telling the sitters (my in-laws). I feel that I need to make sure my baby is safe. And it's peace of mind that I can check in live while I'm at work. My baby cries when I leave him with them and not with anyone else and he always has a diaper rash the next day. My husband doesn't think there an issue. So we are just making sure there isn't.

It's in our livingroom where there's a ton of windows. So no one should be doing anything private there.

*Update: So we used the camera and it did the job. My husband saw what I was afraid of and it was worse than we expected. My baby was not "harmed", but I left a very detailed list and notes and tips and nothing was followed. Breastmilk was warmed in the microwave causing him to spit up every time, genital area wasn't wiped at changes, was not burped, didn't receive his medicine, was left to cry on the floor while she snooped through our house and played on her phone, etc. Because my husband was firm that his mother was babysitting and there was nothing I could do to stop that, I needed to show him why I was against it. It worked. She is no longer allowed to babysit. My husband actually apologized to me. If I would've told her the camera was there, she may have done a better job, who knows. But then she may have been able to babysit him again and we would be subjecting him to drama, swearing, vape steam, diaper rash, bad milk, etc. We don't plan on taking anything to court. And if she found out, she wouldn't do anything because we have evidence of boarder line neglect. It KILLED me to watch it and it disgusted my husband to the point he almost called her a couple times. But he is happy now and okay. I feel horrible my poor baby cried and wasn't properly taken care of. He will never have to be left with her ever again.