According to what we see on this forum, it seems to me that many mothers may be conflicted about how bonded they hope the nanny becomes with the child.
1. Love and care for my child, but we're not going to keep up with any relationship when we're done with you, no matter how attached my child becomes.
or
2. If my child does form a close attachment over time, we hope to maintain whatever relationship might be possible after nanny "moves on."
Personally I'm careful not to be too affectionate with a child in front of the parents. You never know for sure how they'll feel about it. If I think there may be cameras, I'm equally careful. I think that's unfortunate, but most often simple reality.