You're right. In the middle class, the relationship isn't as distinguished. Usually, the salary really is just an "allowance", like the author stated. Other families already consider feeding the help & providing a roof for them as their salary.
Still a very common practice, especially in the Philippines. I'm making stats here based on my personal observation, but here's how it goes:
- The lower class (below or near poverty line) would usually have relatives (sisters or mothers) helping them out
- The middle class are more likely to employ help, especially once they start their own families.
- The upper class definitely employ help. The number of employed help is sometimes even bigger than their own family. And they are treated as employees -- complete with uniforms etc. It's pretty common to see them eat out at a restaurant, and not have the help sit at the same table as them.