Just a quick note- I know ultimateskier and she is NOT at all how you paint her to be. Everyone has bad days and horrible experiences- I think it’s a bit harsh to judge.
I don’t babysit (there’s nobody really in my neighborhood to babysit), but I’ve tutored, and one thing I always appreciated was when the parents stood up for me whatever I said. If I told a kid that she can’t go out and play til we finished (her mom had told me I could have that kind of policy), and she kvetched to mom, she would ALWAYS stand up for me and make the kid stay. If she was misbehaving, the mom would always confront the kid, never excuse her or give her a nosh, like previous posters said. Having a supportive parent in the background really makes life easier.