Only to mention in the listing the sitter will be residing in a separate annexe or most of the house will be out of bounds…
Feels a bit - This is our gorgeous 18th century listed house. You will remain in “the help quarters”. 
I appreciate sometimes if one has the means they may not want sitters in all of their personal space, but I don’t understand showing off your lavish house only to then say it’s not for the sitters to use.
Keep seeing listings like this and it puzzles me.
I would probably report this to MS if it doesn’t show any photos of where the sitter will actually be staying and is therefore inaccurate.
Yes, I have seen this a couple of times. It is basically dishonest, and should be reported.
I’m wondering if you’ve seen the same listing I did. I recently came across one for dog sitting, and funnily enough, it was also for a huge estate. The dog stays in the house, but the sitter actually isn’t allowed access to most of it, just the utility room where you can prepare the dog’s food. Even though the dog can roam freely in and around the house and the garden, and you’re of course expected to take it out for walks, the sitter is only allowed to stay in an annex consisting of a single room that serves as both the bedroom and the kitchen. What’s really interesting is that they were looking for someone to do this for over six weeks!
It’s not this listing as it was different pets, but there does seem to be a few around that follow this theme rather than an anomaly.
We looked after a huge estate in France last summer, with multiple animals. The main picture showed the fabulous chateaux, but we were actually staying in the ‘stables’, and the chateaux was locked up!
But… to be fair, the stables had been converted into a very comfortable, multi-bedroom holiday home, we could enjoy all the grounds, and always had the fabulous views of the chateaux.
All in all it was excellent (and the owners were perfectly clear about the arrangement in the post text and our initial calls)
I think that’s the important thing, here; if pics show the annex/sitters accommodation and the listing is transparent, we have no problem with that. Indeed, we’ve completed a couple of sits where the ‘annex’ was in fact luxurious holiday accommodation and, given that there were none of the owner’s personal belongings present, we were told we could invite guests. We appreciate such generous hosts, but it sounds like these circumstances are a million miles away from those described by the O.P. (which we’ve also noticed, in listings).
We saw one this week where there was a small annex in the garden, which basically comprised 2 rooms plus ensuite. That sounds fine, except we noticed there wasn’t access to a washing machine or dryer (these were in the main house, which was out of bounds). Also, the dog is rather large, which would be problematic in a small space, especially since regular walks on the beach were a requirement. A big, wet, sandy dog in a small annex doesn’t sound like the greatest arrangement to me!
Don’t worry @Happypets - you just need to rinse off the dog each time after walkies. Takes care of one of the 3 (big, wet, sandy) 
After daily walks on the beach, in winter, with 2 lovely labs - early in our sitting adventures - no amount of rinsing off would get rid of all the sand, and that they then proceeded to race me to the sofas meant I hardly sat down to relax throughout the sit. 
I like sits where there are utility rooms or dog rooms, where big breed dogs can dry off after wet and sandy (or muddy) walks!