My current butler is pretty good with the kids but he's an alcoholic. He keeps making drinks for himself every chance he gets. He pretty spoilt too. The family loves him and he's very useful - just alcoholic.
As for nannies, the last one I had won't leave. He remained there even when the mom came home - maybe he was sorry she was a single mom. And no he was not the father of the child. When she dismissed him he came right back an hour later without being called. And he was a very good nanny too - did all the work and cooking and took care of the kids. But he ran up a mean bill so when the toddler grew up and went to school and the mom went back out to work she did not have enough money to pay him.