It's just a sign of a bad employer. How would she feel if her boss complained about how much she caused?
My old MB was like that, complained about how much she paid me despite me being underpaid. They weren't a wealthy family, so I felt a little bad. However, sometimes her giving me my paycheck was awkward and I felt resented.
Well, I ended up living because of that and a slew of other problems. She has yet to find another nanny and it's been four months.