Should you accept a friend request from your maid?

I would if I were you. Since she is already part of your family life, there is nothing much on facebook that she's not aware of i think. At the same time, it offers you a chance to know who are her friends and what is she saying on facebook. Just my two cents. It still very much depends on how comfortable you are and whether you want to draw a clear line between employer and employee for your relationship with her.