To me, "Make yourself at home," means exactly that - treat my home as if it were your own. If I had someone housesitting, I would be perfectly happy for them to eat or drink anything in the place. I wouldn't expect them to go into my personal drawers (any more than I want my husband or kids in there), but anything in the kitchen or bathrooms would be free game to a housesitter to whom I have said "make yourself at home."
If there were any exceptions (and I can't think of anything I've ever had in my house that would be an exception), I would mention them upfront. "Make yourself at home -- except please don't drink the Courvoisier L'Essence de Courvoisier; it cost $3,000 and we're saving it for our Golden wedding."
But to me, taking the tissue paper off the bottle of wine is analogous to going into your personal drawers. I would be totally giving them a pass if the expensive wine was just "in the wine rack" with everything else. I see that it was "in the cabinet" with all the other wine, but it was in the back, and it was wrapped.
So I think I'd say something mildly--it would help them learn something.
This to me is like defrosting the chicken. Something I could NEVER do, even if someone had said, "Make yourself at home, help yourself to food."
Re: the defrosting the chicken--
I did once have a house-sitting gig in which I messed up, and the people told me about it later. She did it nicely, but she definitely said, "You did something that upset us."
They'd specifically TOLD me I should feel free to defrost some of the meat, and mentioned one of it as something that might be extra good. (I lived in a residence hall, so I stayed with their dogs for a full week, not just stopping in, so I could walk them first thing in the a.m. And they told me, "have friends over!") So when I had a friend over, I defrosted the meat so we could cook it. She got REALLY balky about whether we could/should eat it, so I threw up my hands in frustration and we made something else. Then I forgot the meat, and when they got home it was spoiled.
The lady said, "I'm frustrated that it was wasted. If you'd eaten it, as I'd suggested, I wouldn't in the least be mad. But it was expensive, and instead of you enjoying it or us enjoying it, it went in the garbage."
I also accidentally caused minor damage to an vintage toaster they had because I didn't focus on it and the toast burned. She mentioned that as well, and said, "I wish you'd been more careful."
She was non-puntive---more "sharing--and it did keep the air clear between us (I did occasional freelance work for her at her job). And it did help me, to know about those things.
(sorry for typos--the cat is sitting in front of the computer screen, so I have to go with what I can actually see.)