For my current T, I'll copy and paste the conversation from In Session Today that I think inspired this poll. We'd also talked about the topic a bit before.
T: "I know we've discussed this before, how you think a client should be able to say anything in therapy, but as you know, I don't agree with that." Me: "I just keep thinking that this should be the one place where I *can* share anything, that if I can't share it here... And that I should be able to ask you anything, you can just opt not to answer." T: "I don't really think that you can ask anything. Some things wouldn't be appropriate." Me: "Like if, say, I asked you what sorts of things you like to do sexually, that wouldn't be appropriate?" T: "Yes, exactly."

Me: "But I still want to be able to share anything." T: "I just think there are limits, that you don't have to share everything. If a client told me, 'Wow, I really wish you could come on vacation with me and my husband, you could sit at the dinner table with us, and help us work through everything, ha ha!' That's a totally fine thing to share." Me: "OK, that makes sense." T: "But if she were to say to me, 'I have this elaborate sexual fantasy involving you and my husband, and this is the point where I rip off your clothes,' that wouldn't be OK." Me: "Yeah, OK."

So, there are definitely limits with my T, although I wish there weren't. Will mention ex-MC's policy in separate post.

Edited to add: Also in that same session, I told T about my fears of crossing one of those boundaries without being aware he had it (or with him not even being aware it was a boundary until I'd asked). And he did reassure me that it's not like he'd terminate me over it, we'd process it and work through it. So that was good to know.