Yes, I agree 有來有往. But my maid has been working in our house for more than 3 yrs and she never offers our kids any birthday present, christmas presents, etc... not even a bean. I truly understand its difficult for her to buy sth expensive, but simply a birthday card will do (I remember our first Philippine maid gave our son a birthday card which we appreciated).
So, eventhough I still give her Lei See this coming Lunar New Year ($50x2), I still think she does not deserve when I look back into how she treats my kids.
My maid is same as yours. She didn't buy any present to my kids and sometimes showed the black face to my kids. That's why I treat her as employee only even through she worked to me over 3 years.