Short answer: All of what you wrote constitutes a reason why you might never accept another booking from them, but It doesn’t merit a “comfort fee”. Before Booking, you need to consider everything that matters and decide if it’s the right match. It has to be the right match for all involved: The pet(s), The sitter, and the client.
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During the meet and greet, for housesitting you really need to look around, and ask questions. I would definitely ask about where the cameras are positioned. I’ve been in homes where the cameras were filming the common areas (entryways, kitchens, living rooms, dining room), but never in a bedroom/bathroom I’d use.
Hypothetically, if I agreed to sleep on the couch and noticed a Camera was filming me, I would do either one of two options: #1 let them know I was not sleeping well on the couch and as a result was waking up with pains & aches, so I would go home to sleep and return for the first walk in the morning at their usual time. or #2 message them that I was going to cover it for the night and then gently place a something like a dish towel over it. I would be less apt to re-angle a camera because there could be a claim that something broke in doing so.
I wouldn't care about the fact that there wasn’t a storage area to put my belongings. I never unpack and put my clothing in someone else’s furniture anyway. I have more control over keeping my belongings clean how I brought them, rather than putting them in their furnishings and this is for 8 day stay (not months). If that matters to you, you need to discuss and make that arrangement to storage area preference with them prior to booking. In this situation where the cameras are on you, changing clothes in the bathroom is the only solution I’d consider. The fact that the bathroom is small doesn’t merit a comfort fee.
If you choose to ask for a “comfort fee” after the assignment is complete, be prepared for the fact that they might write a really poor review which could impact your chances of future business with other clients. A better approach would be to explain why you weren’t comfortable sleeping there and would not be available for future overnights if they require you to sleep on the couch. If you also include some things that you like about your time with their pet, they might provide you a cash tip in appreciation.