Quick background on the situation. My wife and I bought a vacation house with a friendly couple (we have known each other since the age of 3 - we're practically brothers) that we visit every so often. The house has a live-in caretaker (a 60+ year old woman) that takes care of the house and prepares it for when we visit.
During our last visit, a couple of weeks ago, I discovered that my friend's wife has zero respect for the caretaker's privacy, entering her room without the caretaker's consent.
She does that to get to the east part of the garden quicker since the caretaker's balcony door is right at the edge of the garden, so passing through that room saves her 10 seconds of walking. Another instance was when she retrieved a book from the caretaker's room. This house has a rather large library and the caretaker often borrows books to read at night or on her free time. My friend's wife decided she needed that book and couldn't be bothered to ask her permission to take it.
The caretaker told my wife about it yesterday over the phone and I was a bit dumbfounded at how inconsiderate a person can be. I consider that room as a separate unit that belongs to the caretaker. You wouldn't walk into another person's house to retrieve a book they have borrowed now, would you?
I am thinking of approaching my friend's wife directly but it's going to be a delicate matter.
How can I help her realize that she should respect the caretaker's privacy?
I realize that this is probably only a small part of deeper character flaws and changing her view on the subject might be a colossal task, but I would like to give it a shot as a friend.
Ultimately, I can just ask her to never enter the room again without consent but I am afraid she might push her husband to get the rid of the caretaker. I'd rather avoid that outcome since the caretaker has been working for my family for 20+ or years.