I was mostly joking, but I think this could be argued seriously. While she may not have a legal right to privacy at work, many people argue stringently against employees being spied on by employers (monitoring emails, internet usage, etc). I don’t think this is much different from that except that it’s not the employer doing the spying. From the point of view of a maid though, if I found out someone got clandestine footage of me picking my nose or whatever, I would be annoyed whether or not I worked for them.
Does your right to data security trump the expectation by the maid of not being secretly filmed? Maybe, but it’s not irrelevant.
