Luisa did jobs for cash like working for Scotty and was pushed into an 'arrangement' because of the threat of being found out. Most people who have nannies want someone on the cheap and an illegal with her credentials (ie her mother working for the Butlers) would be quite acceptable - especially for that woman who was so unscrupulous that she wanted her cab driver to 'keep her company' while her husband was playing golf.

I still think Alison going awol has something to do with Ben.